Channel access method and communication apparatus

Abstract

A channel access method and a communication apparatus. The method can be applied to WLAN systems supporting IEEE 802.11ax next-generation Wi-Fi protocols such as 802.11be, Wi-Fi 7 or EHT, and 802.11 series protocols such as 802.11be next-generation and Wi-Fi 8, and can also be applied to UWB-based wireless personal area network systems and sensing systems. In the method, a first station can send a latency signal, so that an opportunity for prioritized channel access can be obtained, thereby reducing channel access latency. In addition, the first station can further perform first backoff before sending the latency signal, thereby reducing the impact of sending latency signals on channel access of conventional devices. In conclusion, the solution can achieve a balance between latency performance and fairness.

Description

A method and communication device for channel access

[0001] This application claims priority to Russian Federal Patent Application No. 2024134234, filed on November 15, 2024, entitled "A Method and Communication Apparatus for Channel Access," the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communications, and more specifically, to a method and apparatus for channel access. Background Technology

[0003] In a wireless local area network (WLAN), each station (STA) shares a channel. To ensure that each STA can access the wireless media without conflicting with each other, the protocol introduces various channel access mechanisms for channel contention, such as the enhanced distributed channel access (EDCA) mechanism.

[0004] Specifically, the EDCA mechanism mainly refers to the following: if the media state is idle for a period of time, the STA can begin a random backoff process. After the random backoff process ends, the STA can send data. The EDCA mechanism allows services of different access categories (ACs) to have different EDCA parameter sets, which can be used for channel access.

[0005] However, the latency performance of this channel access mechanism is not ideal. Summary of the Invention

[0006] This application provides a channel access method and communication device that can not only reduce the latency of channel access, but also reduce the impact of low-latency service channel access on existing equipment. In other words, it can balance latency performance and fairness.

[0007] In a first aspect, a method for channel access is provided, which can be performed by a first site or by components of the first site (e.g., a chip, circuit, or chip system).

[0008] The method includes: performing a first backoff on the channel; and transmitting a first delay signal on the channel when the value of the backoff counter at the first station becomes 0.

[0009] Based on the above scheme, the first station can send a delayed signal, thereby gaining priority access to the channel and reducing the channel access latency. In addition, the first station can also perform a first backoff before sending the delayed signal, thereby reducing the impact on the channel access of traditional equipment due to the transmission of the delayed signal. In summary, the above scheme can balance latency performance and fairness.

[0010] For example, the first delay signal is used to delay the channel access of the second site.

[0011] In conjunction with the first aspect, in some implementations, after sending the first delayed signal, the method further includes: performing a second backoff on the channel; and sending a first radio frame on the channel when the value of the backoff counter of the first station becomes 0.

[0012] Based on the above scheme, after the first backoff is completed and the first delay signal is sent, the first station can also perform a second backoff. When the countdown of the second backoff counter reaches 0, the first station can send the first radio frame. This can reduce the probability of channel collision and improve the efficiency of channel access.

[0013] In conjunction with the first aspect, in some implementations, the method further includes: when the first radio frame is not successfully transmitted, sending a second delay signal on the channel; performing a third backoff on the channel after sending the second delay signal; and retransmitting part or all of the first radio frame on the channel when the backoff counter of the first station becomes 0.

[0014] Based on the above scheme, when the first wireless frame is not successfully transmitted, the first station can send the second delay signal directly on the channel without backing off. This enables the first station to compete for the channel more quickly so as to retransmit the first data and reduce communication latency.

[0015] Optionally, the method further includes: if no acknowledgment frame for the first wireless frame is received within a preset time period after the first wireless frame is sent, determining that the first wireless frame has not been successfully transmitted.

[0016] For example, the initial value of the backoff counter when the first station performs a second backoff is determined based on a second contention window, and the initial value of the backoff counter when the first station performs a third backoff is determined based on a third contention window, wherein the third contention window is greater than or equal to the second contention window.

[0017] In this embodiment of the application, when the first data fails to be transmitted, a third competition window can be set to double the window size of the second competition window, or equal to the second competition window, thereby achieving a balance between backoff time and competition conflict probability.

[0018] In conjunction with the first aspect, in some implementations, the method further includes: performing a fourth backoff on the channel when the first radio frame is successfully transmitted; and sending a third delay signal on the channel when the backoff counter of the first station becomes 0.

[0019] In conjunction with the first aspect, in some implementations, after sending the third delayed signal, the method further includes: performing a fifth backoff on the channel; and sending a second radio frame on the channel when the backoff counter of the first station becomes 0.

[0020] Based on the above scheme, when the first radio frame is successfully transmitted, the first station can also send a third delay signal, thereby gaining priority access to the channel and reducing the channel access latency to transmit the next radio frame. Furthermore, since a fourth backoff is performed before sending the third delay signal, the impact on channel access for traditional devices caused by sending the third delay signal can be reduced. In summary, the above scheme can balance latency performance and fairness.

[0021] For example, the initial value of the backoff counter when the first station performs the first backoff is determined based on the first contention window, and the initial value of the backoff counter when the first station performs the fourth backoff is determined based on the fourth contention window, where the fourth contention window is larger than the first contention window.

[0022] Based on the above scheme, when the first wireless frame is successfully transmitted, the first station can perform a fourth backoff before sending a delayed signal, and the contention window of the fourth backoff is larger than the contention window of the first backoff. This can further reduce the impact on the channel access of traditional devices caused by sending the first delayed signal, that is, it has better fairness.

[0023] As one implementation, the fourth contention window is: CW4 = x * CWmin + (x - 1), where CW4 represents the fourth contention window, CWmin represents the minimum value of the contention window, and x is a positive integer.

[0024] For example, the first competition window is the minimum value of the competition window.

[0025] As an alternative implementation, the fourth contention window is determined based on the number of retransmissions before the first station last had a transmission opportunity.

[0026] For example, the fourth contention window is: CW4 = CWmin + N * (CWmin + 1); or, CW4 = CWmin + (N + 1) * (CWmin + 1); or, CW4 = CWmin + CW(0) + CW(1) + CW(2) + ... + CW(N). Wherein, CW4 represents the fourth contention window, CWmin represents the minimum value of the contention window, N represents the number of retransmissions before the first station obtained a transmission opportunity, CW(i + 1) = 2 * CW(i) + 1, CW(0) = CWmin, i = 0, 1, 2, ..., N-1, and N is a positive integer.

[0027] In one implementation, the initial value of the backoff counter when the first station performs the fifth backoff is determined based on the fifth contention window, which is equal to the second contention window. For example, both the second and fifth contention windows are the minimum values ​​of the contention windows.

[0028] Optionally, the method further includes: determining that the first wireless frame was successfully transmitted when an acknowledgment frame for the first wireless frame is received within a preset time period after the first wireless frame is sent.

[0029] For example, the first competing window is equal to the minimum value of the competing window, and the second competing window is greater than or equal to the minimum value of the competing window.

[0030] In a second aspect, a communication device is provided. The device can be a first station or a component of the first station (e.g., a chip, circuit, or chip system). The device can have the functions described in the first aspect. For example, the device includes modules, units, or means that perform the operations described in the first aspect. These modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0031] Specifically, the device includes: a processing unit for performing a first backoff on the channel; and a transceiver unit for transmitting a first delayed signal on the channel when the value of the backoff counter of the first station becomes 0.

[0032] For example, the first delay signal is used to delay the channel access of the second site.

[0033] In conjunction with the second aspect, in some implementations, after sending the first delayed signal, the processing unit is further configured to: perform a second backoff on the channel; the transceiver unit is further configured to: send a first radio frame on the channel when the backoff counter of the first station becomes 0.

[0034] In conjunction with the second aspect, in some implementations, the transceiver unit is further configured to: send a second delay signal on the channel when the first radio frame fails to be transmitted; the processing unit is further configured to: perform a third backoff on the channel after sending the second delay signal; and the transceiver unit is further configured to: retransmit part or all of the first radio frame on the channel when the backoff counter of the first station becomes 0.

[0035] Optionally, the processing unit is further configured to: determine that the first wireless frame has not been successfully transmitted if no acknowledgment frame is received within a preset time period after the first wireless frame is sent.

[0036] In conjunction with the second aspect, in some implementations, the processing unit is also used to: perform a fourth backoff on the channel when the first radio frame is successfully transmitted; the transceiver unit is also used to: send a third delay signal on the channel when the backoff counter of the first station becomes 0.

[0037] In conjunction with the second aspect, in some implementations, after sending the third delayed signal, the processing unit is further configured to: perform a fifth backoff on the channel; the transceiver unit is further configured to: send a second radio frame on the channel when the backoff counter of the first station becomes 0.

[0038] Optionally, the processing unit is further configured to: determine that the first wireless frame was successfully transmitted when an acknowledgment frame of the first wireless frame is received within a preset time period after the first wireless frame is transmitted.

[0039] It should be understood that any details not fully described in the second aspect and any of its implementations can be found in the first aspect and any of its implementations.

[0040] Thirdly, a communication device is provided, comprising: a memory for storing a program; and at least one processor for executing the computer program or instructions stored in the memory to perform the method provided in the first aspect or its implementation.

[0041] In one implementation, the device is the first station.

[0042] In another implementation, the device is a chip, chip system, or circuit for use in the first site.

[0043] Fourthly, a communication device is provided, comprising: at least one processor and a communication interface, wherein the at least one processor is configured to obtain a computer program or instructions stored in a memory via the communication interface to execute the method provided in the first aspect or its implementation thereof. The communication interface may be implemented in hardware or software.

[0044] In one implementation, the device also includes a memory.

[0045] Fifthly, a processor is provided for executing the method provided in the first aspect above.

[0046] Unless otherwise specified, or if it does not contradict its actual function or internal logic in the relevant description, the transmission and acquisition / reception operations involved in the processor can be understood as processor output and reception, input and other operations, or as transmission and reception operations performed by radio frequency circuits and antennas. This application does not limit them in this regard.

[0047] In a sixth aspect, a computer-readable storage medium is provided that stores program code for execution by a device, the program code including methods for performing the methods provided in the first aspect or its implementations described above.

[0048] In a seventh aspect, a computer program product including instructions is provided, which, when run on a computer, causes the computer to perform the method provided in the first aspect or its implementation.

[0049] Eighthly, a chip is provided, comprising a processor and a communication interface. The processor reads instructions stored in a memory through the communication interface and executes the method provided in the first aspect or its implementation thereof. The communication interface can be implemented in hardware or software.

[0050] Optionally, as one implementation, the chip also includes a memory storing computer programs or instructions, and a processor for executing the computer programs or instructions stored in the memory. When the computer programs or instructions are executed, the processor is used to perform the method provided by the first aspect or its implementation described above.

[0051] When the method provided in this application is executed by a chip, this application does not limit the specific number of chips implementing the method. For example, it can be executed by one chip, or by two or more chips. Furthermore, when the number of chips implementing the method is two or more, the chip manufacturers are not limited; they can be from the same manufacturer or different manufacturers.

[0052] Ninthly, a computer program is provided that, when run on a computer, causes the method provided in the first aspect or its implementation to be executed.

[0053] It should be understood that the beneficial effects of aspects two through nine and any of their implementations can be referenced from aspect one and any of its implementations. Attached Figure Description

[0054] Figure 1 is a schematic diagram of a network architecture applicable to an embodiment of this application.

[0055] Figure 2 is a schematic diagram of a channel access process.

[0056] Figure 3 illustrates an example of a random backoff process among multiple sites based on a point coordination mechanism.

[0057] Figure 4 shows an example of an exponentially growing competition window.

[0058] Figure 5 is a schematic diagram of high-priority channel access.

[0059] Figure 6 is a schematic flowchart of a channel access method 600 provided in this application.

[0060] Figures 7 to 12 are schematic diagrams comparing the effects of the channel access method of this application.

[0061] Figures 13 and 14 are schematic diagrams of the structure of the communication device provided in the embodiments of this application. Detailed Implementation

[0062] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0063] The embodiments of this application can be applied to wireless local area networks (WLANs), for example, supporting IEEE 802.11 related standards, such as 802.11a / b / g standards, 802.11n standards, 802.11ac standards, 802.11ax standards (i.e., Wi-Fi 6, also known as the high efficient (HE) standard), 802.11be standards (i.e., Wi-Fi 7, also known as the extremely high throughput (EHT) standard), 802.11bn standards (i.e., Wi-Fi 8, also known as the ultra high reliability (UHR) standard) or next-generation Wi-Fi 8 standards, and also include 802.11ad, 802.11ay standards, etc. The embodiments of this application can also be applied to wireless local area network systems that support integrated millimeter wave (IMMW), wireless local area network systems that support ultra-wideband (UWB) such as the 802.15 series standards, sensing systems such as the 802.11bf series standards, or wireless positioning such as 802.11az. This application can also support standard protocols such as spark link and near link.

[0064] Although the embodiments of this application are primarily illustrated using the deployment of WLAN networks, particularly those employing the IEEE 802.11 system standard, those skilled in the art will readily understand that the various aspects involved in the embodiments of this application can be extended to other networks employing various standards or protocols, such as high-performance radio local area networks (HIPERLANs), wireless wide area networks (WWANs), wireless personal area networks (WPANs), or other networks now known or developed in the future. Therefore, regardless of the coverage area and wireless access protocol used, the various aspects provided in the embodiments of this application can be applied to any suitable wireless network.

[0065] The technical solutions of this application embodiment can also be applied to various communication systems, such as: WLAN communication systems, wireless fidelity (Wi-Fi) systems, 5th generation (5G) systems or new radio (NR) systems, 6th generation (6G) systems, Internet of Things (IoT) networks or vehicle-to-everything (V2X) networks, etc.

[0066] The communication systems described above that are applicable to this application are merely illustrative examples, and the communication systems applicable to this application are not limited to these. They will be uniformly described here and will not be repeated below.

[0067] Figure 1 is a schematic diagram of an application scenario applicable to an embodiment of this application. As shown in Figure 1, the method provided by this application is applicable to data communication between stations (STAs), where a station can be an access point (AP) type station or a non-access point station (non-AP STA), referred to as AP and non-AP stations respectively. Specifically, the solution of this application is applicable to communication between an AP and one or more non-AP stations (e.g., communication between AP1 and non-AP STA1, non-AP STA2), communication between APs (e.g., communication between AP1 and AP2), and communication between non-AP STAs (e.g., data communication between non-AP STA2 and non-AP STA3). Unless otherwise specified in this application, a station (or STA) includes both non-AP STAs and APs; that is, a station (or STA) can be either a non-AP STA or an AP.

[0068] An Access Point (AP) can be a node that allows terminals (such as mobile phones) to access a wired (or wireless) network. It is primarily deployed in homes, buildings, and campuses, with a typical coverage radius of tens to hundreds of meters. Of course, it can also be deployed outdoors. An AP acts as a bridge connecting wired and wireless networks, its main function being to connect various wireless network clients together and then connect the wireless network to the Ethernet.

[0069] Specifically, an AP can be a terminal or network device with a Wi-Fi chip. This network device can be a server, router, switch, bridge, computer, mobile phone, relay station, vehicle-mounted equipment, wearable device, network device in a 5G network, network device in a 6G network, or network device in a public land mobile network (PLMN), etc., and this application embodiment is not limited to these. The AP can be a device that supports Wi-Fi standards. For example, the AP can also support one or more standards in the IEEE 802.11 series, such as 802.11be and 802.11be next generation.

[0070] Non-AP sites can be wireless communication chips, wireless sensors, or wireless communication terminals, and may also be referred to as users, user equipment (UE), access terminals, user units, user stations, mobile stations, mobile stations, remote stations, remote terminals, mobile devices, user terminals, terminals, wireless communication equipment, user agents, or user devices. Non-AP sites can be cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, IoT devices, wearable devices, terminal devices in 5G networks, terminal devices in 6G networks, or terminal devices in PLMNs, etc., and this application embodiment is not limited to these. Non-AP sites can be devices that support WLAN standards. For example, non-AP sites can support one or more standards in the IEEE 802.11 series, such as 802.11be and 802.11be next generation.

[0071] For example, non-AP sites can be mobile phones, tablets, set-top boxes, smart TVs, smart wearable devices, vehicle communication devices, computers, Internet of Things (IoT) nodes, sensors, smart home devices such as smart cameras, smart remote controls, smart water and electricity meters, and sensors in smart cities.

[0072] The aforementioned AP or non-AP sites may include transmitters, receivers, memory, processors, etc., wherein the transmitter and receiver are used for transmitting and receiving packet structures, respectively, the memory is used for storing signaling information and pre-agreed preset values, etc., and the processor is used for parsing signaling information and processing related data, etc.

[0073] In WLANs, all STAs share a channel. To ensure that each STA can access the wireless media without collisions, various channel access mechanisms are introduced in the protocol to handle channel contention, such as the distributed coordination function (DCF), enhanced distributed channel access (EDCA), and high priority (HiP) channel access. For ease of understanding, this application will first provide a brief introduction to these various channel access mechanisms.

[0074] 1. DCF mechanism

[0075] DCF (Distributed Channel Function) is a basic access method in the 802.11 wireless LAN standard. It has excellent distributed characteristics and is therefore widely used. To ensure that STAs can access the wireless medium without collisions, the specific protocol mechanism employed by DCF includes Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). The basic idea of ​​CSMA / CA is that when a STA intends to transmit data, it needs to perform a clear channel access (CCA) assessment of the wireless medium. If the medium state is idle for a period of time (such as the DCF inter-frame spacing (DIFS)), the STA can begin a random backoff process. If the medium state is busy, the STA must wait for the medium to become idle and maintain this state for a period of time (such as DIFS) before initiating the random backoff process. After the random backoff process is completed, the STA can transmit data.

[0076] CSMA / CA is based on carrier sensing (CS), which includes physical carrier sensing and virtual carrier sensing. In other words, it uses both physical and virtual carrier sensing functions to determine the media status. Physical carrier sensing resides in the physical layer (PHY) and determines media busyness through energy detection (ED) and preamble detection (PD). Virtual carrier sensing resides in the media / medium access control (MAC) layer and determines channel idleness through the duration field in the received radio frame. Specifically, after receiving a radio frame, the STA sets the network allocation vector (NAV) value in the duration field. The NAV value indicates the length of time the STA sending the radio frame needs to occupy the channel. After setting the NAV, the STA starts a countdown. When the countdown reaches 0, the channel is idle. The NAV countdown value can also be called the remaining backoff time. The STA determines that the channel is idle only if both the physical carrier sensing and virtual carrier sensing mechanisms detect that the channel is idle; otherwise, it determines that the channel is busy.

[0077] Figure 2 is a schematic diagram of a basic access procedure for the CSMA / CA mechanism. As shown in Figure 2, when the channel changes from busy to idle, the STA initiates a random backoff process after a certain period. This period can be any one of DIFS, point coordination function interframe space (PIFS), or short interframe space (SIFS). During the random backoff process, the STA determines the random backoff time to be rolled back. The backoff window in Figure 2 corresponds to the random backoff time. The method for determining the random backoff time will be explained in detail after Figure 3.

[0078] Figure 3 illustrates an example of a random backoff process among multiple STAs based on the DCF mechanism. As shown in Figure 3, initially, STA A sends a data frame, while STA B, STA C, and STA D all delay sending their data frames. After STA A finishes sending its data frame (i.e., the channel becomes idle), STA B, STA C, and STA D remain idle for a period before initiating the random backoff process. At time #1, STA C completes the random backoff process first, sending its data frame, while STA B and STA D freeze their remaining backoff time, as shown by the gray shaded area in Figure 3. While STA C is sending its data frame, STA E delays its data frame transmission. After STA C finishes sending its data frame (i.e., the channel becomes idle), STA B, STA D, and STA E remain idle for a period before initiating the random backoff process. At time #2, STA D completes the random backoff process first, sending its data frame, while STA B and STA E freeze their remaining backoff time, as shown by the shaded area in Figure 3. This continues until time #3, when STA E completes the random backoff process and sends its data frame. At time #4, STA B completes the random backoff process and sends a data frame.

[0079] The following is a brief introduction to how the STA determines the random backoff time required. For example, the random backoff time required by the STA is a random backoff value multiplied by the time of each time slot. The random backoff value is randomly selected from a uniformly distributed window [0, CW]. The contention window (CW) has multiple values. It is initialized to its minimum value (CWmin) during the initial attempt. Each time a transmission fails (e.g., a collision occurs), a retransmission is required, and CW increases progressively until it reaches its maximum value (CWmax). When data is successfully transmitted, CW is reset to CWmin. The size of each window is a factor of 2 minus 1, and approximately twice the size of the previous window; for simplicity, this is referred to as window doubling.

[0080] Figure 4 illustrates an example of exponentially growing CW. As shown in Figure 4, the CW is 7 (i.e., 2) when STA first attempts. 3 -1). During the first retransmission, CW is 15 (i.e., 2). 4 -1, or 7*2+1), CW is 31 (i.e., 2) during the second retransmission. 5 -1, or 15*2+1), CW is 63 (i.e. 2) during the third retransmission. 6 -1, or 31*2+1), and so on, until the fourth retransmission when CW is 127 (i.e., 2). 7 -1, or 63*2+1), the CW is 255 (i.e., 2) during the fifth retransmission. 8 -1, or 127*2+1), since CWmin is 7 and CWmax is 255, CW is 255 for each retransmission after the fifth retransmission.

[0081] 2. EDCA Mechanism

[0082] The EDCA mechanism is an enhancement of the DCF mechanism. It allows services of different access categories (ACs) to have different sets of EDCA parameters, including CWmin, CWmax, and arbitration interframe space (AIFS). The EDCA parameters for different ACs are shown in Table 1.

[0083] Table 1

[0084] In Table 1, AIFSN represents the arbitration inter-frame spacing number (AIFSN), TXOP represents the transmit opportunity (TXOP), TXOP limit represents the maximum number of transmit opportunities, AC_BK, AC_BE, AC_VI, and AC_VO represent the best effort access category (AC_BE), background access category (AC_BK), voice access category (AC_VO), and video access category (AC_VI), respectively, and legacy represents the legacy access category. Different access categories can also represent different service types.

[0085] For a specific AC service, the backoff process is basically the same as the DCF mechanism, except that AIFS replaces DIFS in the DCF mechanism. That is, when the channel returns to idle, the STA must wait for AIFS before initiating the backoff process. AIFS is calculated as AIFS[AC] = aSIFSTime + AIFSN[AC] * aSlotTime. For example, for a service with access level AC_BE, its EDCA parameter set is {CWmin = 31, CWmax = 1023, AIFSN = 3}. Therefore, during the EDCA backoff process, AIFS is aSIFSTime + 3 * aSlotTime. That is, when the channel returns to idle, the STA must wait for aSIFSTime + 3 * aSlotTime before initiating the backoff process. aSlotTime represents the length of the time slot, typically 9µs. aSIFSTime represents the length of SIFS. Furthermore, the initial value of the backoff counter should be randomly generated from [0, 31]. The AP sends an EDCA parameter set in the beacon frame, and all STAs use the EDCA parameters sent by the AP in the beacon frame to compete for the EDCA channel.

[0086] The EDCA mechanism allows different ACs to have different EDCA parameter sets, which enables priority-based channel access transmission services for different types of services. For example, the CWmin of AC_VI and legacy services is the CWmax of AC_VO, and the CWmin of AC_BK and AC_BE is the CWmax of AC_VI. This makes AC_VO's access priority higher than AC_VI and legacy services, and AC_VI's access priority higher than AC_BK and AC_BE. In other words, it makes AC_VO's access latency lower than AC_VI and legacy services, and AC_VI's access latency lower than AC_BK and AC_BE.

[0087] 3. High-priority (HiP) channel access

[0088] With the development of WLAN, the volume of low-latency traffic (LLT) is increasing, and LLT services require the system to successfully transmit packets in a shorter time. Although the EDCA mechanism can reduce the access latency of some services, its latency performance is still not ideal in some scenarios. To address this, the protocol introduces a high-priority (HiP) channel access mechanism. The high-priority channel access mechanism makes it easier for sites to obtain channel access opportunities and reduces channel access latency.

[0089] Specifically, the basic idea of ​​HiP channel access (or HiP mechanism) is that during the EDCA channel contention process, when the channel changes from busy to idle, a delayed signal (DS) can be sent at intervals of DIFS. After receiving the DS, other STAs stop competing for the channel, thus making it easier for the STA to obtain the opportunity to access the channel.

[0090] Figure 5 is a schematic diagram of high-priority channel access. As shown in Figure 5, STA1 and STA2 are saturated devices (or legacy devices that do not support HiP channel access), while STA3 and STA4 are new devices that support HiP channel access. After STA1 finishes its previous transmission opportunity, all STAs compete for the next transmission opportunity. STA3 and STA4, being new devices supporting HiP channel access, send a Data Frame (DS) immediately after the DIFS following the previous transmission opportunity. STA1 and STA2 stop competing for the channel upon receiving the DS. Subsequently, STA3 and STA4 perform further backoff, and data transmission occurs after the backoff is complete. As shown in Figure 5, STA3 completes the backoff first, therefore STA3 sends the data frame first. It should be understood that for STA1 or STA2 to correctly receive the DS, the content of the DS sent by all STAs must be identical. The Data Sensing (DS) can consist of only the legacy short training field (L-STF), the legacy long training field (L-LTF), and the legacy signal field (L-SIG). This allows stations to resume channel contention only after receiving the DS, with an extended inter-frame space (EIFS) interval. The length of the EIFS is sufficient for the station sending the DS to back off, thus granting it higher channel access priority. Alternatively, the DS can be a short frame, such as a clear to send (CTS) frame, which includes a duration field. This allows the station receiving the DS to set a Non-Volume Availability (NAV), preventing channel contention during the NAV period. As shown in Figure 5, after receiving the DS, STA 1 and STA 2 can either refrain from channel contention for the EIFS duration or set an NAV, preventing channel contention until the NAV countdown reaches 0.

[0091] In the above approach, since the STA does not need to backoff before sending DS, STAs with HiP channel access capabilities have more channel access opportunities compared to traditional STAs, leading to a certain degree of unfairness. Therefore, one approach is to only send DS during retransmissions, meaning that HiP channel access can only be used for channel access after the first transmission failure.

[0092] Low latency is a key research goal for WLAN standards. 802.11be introduced Restricted Target Wake Time (R-TWT) to improve support for low-latency services. R-TWT pre-allocates service periods based on periodic services and gives high access priority to low-latency services within those periods. While R-TWT improves support for low-latency services, next-generation WLAN standards (e.g., 802.11bn) place even higher demands on low latency, requiring ultra-low latency of less than a few milliseconds. Current WLAN standards only send DS (Data Streaming) during retransmissions, resulting in suboptimal latency performance. Furthermore, with the development of WLAN, the traffic volume of low-latency services is increasing, potentially leading to more retransmissions and thus more DS transmissions. Sending these DSs can significantly impact channel access for existing devices.

[0093] In view of this, this application proposes a channel access method and communication device that can not only reduce the latency of channel access, but also reduce the impact of low-latency service channel access on existing equipment, that is, it can balance latency performance and fairness.

[0094] It should be understood that the embodiments shown below use a first station as the execution subject to illustrate the method, but this application does not limit the execution subject. Any program capable of running the code of the method provided in the embodiments of this application can communicate according to the method provided in the embodiments of this application. The execution subject of the method provided in the embodiments of this application can be a first station, or a functional module within the first station capable of calling and executing a program. For example, the first station in Figure 6 can also be a chip, chip system, or processor that supports the method implemented by the first station, or it can be a logic module or software capable of implementing all or part of the functions of the first station.

[0095] Figure 6 is a schematic flowchart of a channel access method 600 provided in this application. As shown in Figure 6, the method 600 includes the following steps.

[0096] S610, the first station performs the first backoff on the first channel.

[0097] In this application, the first site can be any site that needs to access the channel; it can be an AP or a non-AP STA, and there is no limitation.

[0098] The first channel can be any channel in the WLAN, and this application does not limit its operating frequency.

[0099] In this application, the retreat (such as the first retreat and the second, third, fourth and fifth retreats below) refers to a random retreat process in which the first station starts a retreat counter and counts down over time until the countdown reaches 0.

[0100] For example, the first backoff may be initiated when a low-latency service data packet appears in the buffer queue of the first site, or it may be initiated in advance, that is, the first backoff may be started in advance before the low-latency service data packet arrives, or it may be initiated after some low-latency service data packets have been transmitted in order to continue transmitting other low-latency service data packets.

[0101] For example, the first station may execute S610 when it determines that the first channel is in an idle state and the duration of the idle state is greater than a certain duration (e.g., DIFS or AIFS).

[0102] S620, when the backoff counter value of the first station becomes 0, the first station sends a first delayed signal on the first channel.

[0103] In this application, "when..." can be replaced with "in the case of...", "if..., then...", "if..., then...", etc.

[0104] In this context, the value of the backoff counter at the first station becomes 0, or in other words, the countdown of the backoff counter at the first station reaches 0. It should be understood that the backoff counter mentioned in S620 can be understood as the backoff counter started when the first station performs its first backoff, and it can also be called the first backoff counter.

[0105] Optionally, the initial value of the first backoff counter can be determined based on the first contention window (denoted as CW1). For example, the initial value of the first backoff counter can be randomly selected from a uniformly distributed window [0, CW1]. Exemplarily, the first contention window can be the minimum value of the contention window (denoted as CWmin). Specifically, CWmin can be determined based on the AC of the service to be transmitted in this first backoff, for example, as shown in Table 1.

[0106] In this application, the numerical range [a, b] can also be denoted as a~b, which refers to all integers including a and b, as well as those between a and b. For example, [0, 7] refers to 0, 1, 2, 3, 4, 5, 6, 7.

[0107] In one implementation, the delay signals (such as the first delay signal and the second and third delay signals described below) are used to delay the channel access of the second station. That is, after receiving the delay signal, the second station can stop competing for the channel and delay its access to the channel, thereby giving the first station a priority to access the channel. The second station can be any other station besides the first station.

[0108] For example, the first delayed signal and the second and third delayed signals described below in this application all have the same format. For instance, all of the above delayed signals include L-STF, L-LTF, and L-SIG. Furthermore, all of the above delayed signals are CTS frames, which include a duration field. The value of the duration field can be DIFS + 7 * aSlotTime (i.e., 34us + 7 * 9us = 97us), or the value of the duration field can be 7 * aSlotTime (i.e., 7 * 9us = 63us), or the value of the duration field can be a value greater than 63us, such as 94us or 100us. Also, all of the above delayed signals are request-to-send (RTS) frames. Optionally, the formats of the first delayed signal and the second and third delayed signals described below can also be different, and are not limited thereto.

[0109] Based on the above scheme, the first station can send a delayed signal, thereby gaining priority access to the channel and reducing the channel access latency. In addition, the first station can also perform a first backoff before sending the delayed signal, thereby reducing the impact on the channel access of traditional equipment due to the transmission of the delayed signal. In summary, the above scheme can balance latency performance and fairness.

[0110] Optionally, after sending the first delayed signal, the method 600 further includes: S630, the first station performs a second backoff on the first channel; when the value of the backoff counter of the first station becomes 0, the first station sends a first radio frame on the first channel.

[0111] It should be understood that the backoff counter mentioned in S630 can be understood as the backoff counter started when the first station performs a second backoff, and it can also be called the second backoff counter.

[0112] Optionally, the initial value of the second backoff counter can be determined based on a second contention window (denoted as CW2). For example, the initial value of the second backoff counter can be randomly selected from a uniformly distributed window [0, CW2]. Exemplarily, the second contention window can be smaller than the first contention window, or it can be greater than or equal to the first contention window.

[0113] The first radio frame can be a data frame or a control frame, such as an RTS frame, and is not limited to any particular type. When the first radio frame is a data frame, it can refer to a single data packet or consist of multiple data packets.

[0114] For example, the first backoff and the second backoff can be understood as two backoffs in a channel contention process.

[0115] Based on the above scheme, after the first backoff is completed and the first delay signal is sent, the first station can also perform a second backoff. When the countdown of the second backoff counter reaches 0, the first station can send the first radio frame. This can reduce the probability of channel collision and improve the efficiency of channel access.

[0116] Optionally, the first station has not transmitted the first radio frame before S610. That is, S630 is the first transmission or initial transmission of the first radio frame.

[0117] In other words, the solution of this application can send a delayed signal during the initial transmission. Compared with sending a delayed signal only during retransmission, this solution can reduce the channel access delay and thus have better delay performance.

[0118] Optionally, after S630, the method 600 further includes: S601, whereby the first station determines whether the first radio frame was successfully transmitted.

[0119] For example, if the first station does not receive an acknowledgment frame for the first wireless frame within a preset time period after the first wireless frame is sent, the first station can determine that the first wireless frame has not been successfully transmitted. If the first station receives an acknowledgment frame for the first wireless frame within the preset time period after the first wireless frame is sent, the first station can determine that the first wireless frame has been successfully transmitted.

[0120] The specific duration of the preset duration can be a value predefined by the protocol. For example, the preset duration can be PIFS or DIFS, etc.

[0121] It should be understood that if the first radio frame consists of multiple data packets, after the first station sends the first radio frame, if the second station successfully receives some or all of the multiple data packets, the second station will reply with an acknowledgment frame. The acknowledgment frame indicates the successfully transmitted content, such as which data packets were successfully transmitted. Thus, the first station can determine that one or more data packets in the first radio frame were successfully transmitted, and can therefore consider the first radio frame to have been successfully transmitted. If the second station fails to receive any data packet from the first radio frame, then the second station will not reply with an acknowledgment frame, and the first station can confirm that none of the multiple data packets in the first radio frame were successfully transmitted.

[0122] Based on the above scheme, after sending the first wireless frame, the first station can determine whether the first wireless frame has been successfully transmitted, and thus determine whether the first wireless frame needs to be retransmitted to ensure the reliability of the transmission.

[0123] As one implementation, when the first radio frame fails to be transmitted, method 600 also includes steps S640a and S650a. That is, when the first radio frame fails to be transmitted, the first station can execute steps S640a and S650a.

[0124] Specifically, in S640a, the first station transmits a second delayed signal on the first channel.

[0125] S650a, after sending the second delayed signal, the first station performs a third backoff on the first channel; when the value of the backoff counter of the first station becomes 0, the first station retransmits part or all of the first radio frame on the first channel.

[0126] It should be understood that the backoff counter mentioned in S650a can be understood as the backoff counter started when the first station performs the third backoff, and it can also be called the third backoff counter.

[0127] In other words, when the first radio frame fails to be transmitted, the first station can directly send a second delayed signal on the channel, and perform a third backoff after the second delayed signal is sent. When the countdown of the third backoff counter reaches 0, the first station can retransmit the first radio frame. Specifically, it can retransmit the entire first radio frame or a part of the first radio frame.

[0128] For example, the first radio frame is not successfully transmitted, which can also be referred to as the first radio frame transmission failure, or the first radio frame not being sent successfully, or the first station failing to compete for the first channel, or the first station failing to compete for the first channel, or the first station not obtaining the TXOP, or the first station not successfully obtaining the TXOP, etc.

[0129] Optionally, S640a and S650a can be understood as the first retransmission of the first radio frame. If the first retransmission of the first radio frame in S640a and S650a still fails, the first station can repeat S640a and S650a.

[0130] Based on the above scheme, when the first wireless frame is not successfully transmitted, the first station can send the second delay signal directly on the channel without backing off. This enables the first station to compete for the channel more quickly so as to retransmit the first data and reduce communication latency.

[0131] Optionally, the initial value of the third backoff counter can be determined based on a third contention window (denoted as CW3). For example, the initial value of the third backoff counter can be randomly selected from a uniformly distributed window [0, CW3]. Exemplarily, the third contention window can be greater than or equal to the second contention window. For example, the third contention window can be equal to CW2, or the third contention window can be doubled based on the second contention window, i.e., CW3 can be equal to CW2*2+1.

[0132] It is understandable that a larger contention window during channel contention results in a lower probability of contention conflict, but a longer backoff time; conversely, a smaller contention window results in a shorter backoff time, but a higher probability of contention conflict. In this embodiment, when the first data fails to transmit successfully, a third contention window can be set that is doubled or equal to the second contention window, thereby achieving a balance between backoff time and the probability of contention conflict.

[0133] As one implementation method, in S640a, backoff can also be performed before the first station sends the second delay signal, for example, called the sixth backoff. In this case, the first station sending the second delay signal can mean that the first station sends the second delay signal when the value of the backoff counter of the first station (i.e. the backoff counter started when the sixth backoff is performed, which can be simply referred to as the sixth backoff counter) becomes 0.

[0134] For example, the initial value of the sixth backoff counter can be determined based on the sixth competition window (denoted as CW6). For instance, the initial value of the sixth backoff counter can be randomly selected from a uniformly distributed window [0, CW6].

[0135] Optionally, when the first station performs the sixth backoff, the third and sixth backoffs can be understood as two backoffs in a single channel contention process. Alternatively, when the first station does not perform the sixth backoff, the current channel contention only includes the third backoff and does not include the sixth backoff.

[0136] As another implementation, when the first radio frame is successfully transmitted, method 600 also includes S640b and S650b. That is, when the first radio frame is successfully transmitted, the first station can execute S640b and S650b.

[0137] Specifically, in S640b, the first station performs a fourth backoff on the first channel; when the value of the backoff counter of the first station becomes 0, the first station sends a third delayed signal on the first channel.

[0138] In S650b, after sending the third delayed signal, the first station performs a fifth backoff on the first channel; when the value of the backoff counter of the first station becomes 0, the first station sends a second radio frame on the first channel.

[0139] It should be understood that the backoff counter mentioned in S640b can be understood as the backoff counter started when the first station performs the fourth backoff, and it can also be called the fourth backoff counter. The backoff counter mentioned in S650b can be understood as the backoff counter started when the first station performs the fifth backoff, and it can also be called the fifth backoff counter.

[0140] In other words, when the first radio frame is successfully transmitted, the first station can perform a fourth backoff on that channel. When the fourth backoff counter counts down to 0, it sends a third delay signal, and after the third delay signal is sent, it performs a fifth backoff. When the fifth backoff counter counts down to 0, the first station can send the next radio frame, i.e., the second radio frame. Optionally, the second radio frame can be completely different from the first radio frame.

[0141] For example, the successful transmission of the first radio frame can also be referred to as the successful transmission of the first radio frame, or the successful contention of the first station for the first channel, or the successful acquisition of the TXOP by the first station, or the successful acquisition of the TXOP by the first station, or the successful acquisition of the TXOP by the first station, etc.

[0142] Optionally, S640a and S650a can be understood as a loop from S610 to S630. If the second wireless frame is successfully transmitted in S640b and S650b, then the first station can continue to loop S640b and S650b.

[0143] For example, the fourth backoff can be initiated when there are still low-latency service data packets after the first station has sent the first radio frame, or it can be initiated when the current low-latency service data packets have been sent, but the first station needs to prepare for the next transmission of low-latency service data packets.

[0144] Based on the above scheme, when the first radio frame is successfully transmitted, the first station can also send a third delay signal, thereby gaining priority access to the channel and reducing the channel access latency to transmit the next radio frame. Furthermore, since a fourth backoff is performed before sending the third delay signal, the impact on channel access for traditional devices caused by sending the third delay signal can be reduced. In summary, the above scheme can balance latency performance and fairness.

[0145] The backoff counter mentioned in S640b can be understood as the backoff counter started when the first station performs the fourth backoff, and it can also be called the fourth backoff counter. The backoff counter mentioned in S650b can be understood as the backoff counter started when the first station performs the fifth backoff, and it can also be called the fifth backoff counter.

[0146] Optionally, the initial value of the fourth backoff counter can be determined based on a fourth contention window (denoted as CW4). For example, the initial value of the fourth backoff counter can be randomly selected from a uniformly distributed window [0, CW4]. Exemplarily, the fourth contention window can be larger than the first contention window. Several examples of determining the fourth contention window are given below.

[0147] Example 1: Assume the first competition window is CWmin, and the fourth competition window is: CW4 = x * CWmin + (x - 1), where x is a positive integer.

[0148] For example, x can be 2, and CW4 can be set to 2*CWmin+1. Or, x can be 4, and CW4 can be set to 4*CWmin+3, and so on.

[0149] Example 2: The fourth contention window is determined based on the number of retransmissions before the first station last acquired the TXOP. Alternatively, the fourth contention window is determined based on the number of retransmissions when the first station last acquired the TXOP, or the fourth contention window is determined based on the number of transmissions before the first station last acquired the TXOP, or the fourth contention window is determined based on the number of transmissions when the first station last acquired the TXOP. For ease of explanation, any of the above numbers can be denoted as N, where N is a positive integer.

[0150] It is understandable that the number of transmissions includes the initial transmission, the number of retransmissions does not include the initial transmission, and the number of transmissions before obtaining the TXOP does not include the transmission at the time of obtaining the TXOP. For example, suppose the first station fails on the first transmission and obtains the TXOP on the third retransmission, then:

[0151] The number of retransmissions before the first site receives the TXOP is 2, excluding the 3rd retransmission.

[0152] The number of retransmissions when the first site obtains a TXOP is 3, which includes the 3rd retransmission.

[0153] The number of transmissions before the first site obtains the TXOP is 3, which does not include the 3rd retransmission, but includes the 1st transmission.

[0154] The number of transmissions when the first site obtains the TXOP is 4, which includes the 3rd retransmission and the 1st transmission.

[0155] In this example, assuming the first competition window is CWmin, the fourth competition window can be determined by any one of the following equations (1) to (3). CW4=CWmin+N*(CWmin+1) (1) CW4=CWmin+(N+1)*(CWmin+1) (2) CW4=CWmin+CW(0)+CW(1)+CW(2)+...+CW(N) (3)

[0156] Among them, in formula (3), CW(i+1)=2*CW(i)+1, CW(0)=CWmin, i=0,1,2,...,N-1. For example, assuming N=3, then CW(0)=CWmin, CW(1)=2*CW(0)+1=2*CWmin+1, CW(2)=2*CW(1)+1=2*(2*CWmin+ 1)+1=4*CWmin+3, CW(3)=2*CW(2)+1=2*(4*CWmin+3)+1=8*CWmin+7, therefore, CW4=15*CWmin+11.

[0157] Based on the above scheme, when the first wireless frame is successfully transmitted, the first station can perform a fourth backoff before sending a delayed signal, and the contention window of the fourth backoff is larger than the contention window of the first backoff. This can further reduce the impact on the channel access of traditional devices caused by sending the first delayed signal, that is, it has better fairness.

[0158] For example, the value of any competition window in this application (e.g., the first competition window, the second competition window, the third competition window, the fourth competition window, and the fifth competition window hereinafter) does not exceed the maximum value of the competition window (denoted as CWmax). Specifically, CWmax can be determined based on the AC of the service to be transmitted in this backoff, for example, as shown in Table 1.

[0159] Optionally, the initial value of the fifth backoff counter can be determined based on the fifth contention window (denoted as CW5). For example, the initial value of the fifth backoff counter can be randomly selected from a uniformly distributed window [0, CW5]. Exemplarily, the fifth contention window can be equal to the second contention window. For example, both the second and fifth contention windows are CWmin.

[0160] It should be understood that the specific values ​​of each competing window in this application are independent of each other. That is to say, the specific value of any competing window can be greater than, less than or equal to other competing windows. The size relationship between the competing windows given above is only an example and is not a limitation.

[0161] For example, the fourth backoff and the fifth backoff can be understood as two backoffs in a channel contention process.

[0162] The method of this application has been described in detail above with reference to Figure 6. The effects of the above method are briefly explained below with reference to Figures 7 to 12.

[0163] Assume a communication scenario with 9 STAs, including 1 AP and 8 non-APSTAs. Four of the non-APSTAs are existing devices, all with their queues fully loaded with non-low-latency services. The other four non-APSTAs are new devices capable of supporting schemes A through E for transmitting low-latency services. Specifically, scheme A is the EDCA mechanism specified in the protocol; scheme B is based on a high-priority channel access mechanism, sending a delay signal only during the first retransmission; scheme C is also a high-priority channel access mechanism, sending a delay signal only during retransmissions; scheme D is based on a high-priority channel access mechanism, sending a delay signal before each transmission (including initial and retransmissions); and scheme E is the channel access method of this application. In comparison, the existing devices can only support scheme A of the above five schemes, not schemes B through E. Therefore, when new devices use schemes B through E for channel access, existing devices still use scheme A.

[0164] In Figures 7 to 12, the horizontal axis represents the time interval T between two adjacent data packets in low-latency services, in seconds (s). A larger interval indicates less traffic in the low-latency service, and a smaller interval indicates more traffic. In other words, from left to right, the horizontal axis in Figures 7 to 12 represents a decreasing traffic volume for low-latency services. Furthermore, the A, B, C, D, and E above the bars in Figures 7 to 12 represent the channel access mechanisms adopted by the new equipment: Scheme A, Scheme B, Scheme C, Scheme D, and Scheme E, respectively.

[0165] Figure 7 is a schematic diagram of the throughput of existing equipment. As shown in the left half of Figure 7, when the traffic volume of low-latency services is relatively large (as shown by the horizontal axis of 0.004, 0.01, or 0.02 in Figure 7), for each traffic volume (for example, at the horizontal axis of 0.004 in Figure 7), when the new equipment adopts scheme E, the throughput of the existing equipment is less different from that of the new equipment adopting scheme A (as shown by a1 and a2 in Figure 7). In contrast, when the new equipment adopts scheme B, scheme C, or scheme D, the throughput of the existing equipment is significantly different from that of the new equipment adopting scheme A (as shown by a1 and a3 in Figure 7, or a1 and a4 in Figure 7, or a1 and a5 in Figure 7). In other words, compared with schemes B, C, and D, scheme E can improve the throughput of existing equipment, thereby reducing the impact of low-latency service transmission on the channel access of traditional equipment and providing better fairness.

[0166] Figure 8 is a schematic diagram of the throughput of the new equipment. As shown in the left half of Figure 8, when the traffic volume of low-latency services is relatively large (as shown by the horizontal axis at 0.004, 0.01, or 0.02 in Figure 8), for each traffic volume (for example, at the horizontal axis at 0.004 in Figure 8), when the new equipment adopts scheme E, the throughput of the new equipment is less different from that of the new equipment adopting scheme A (as shown by b1 and b2 in Figure 7). In contrast, when the new equipment adopts schemes B, C, or D, the throughput of the new equipment is significantly different from that of the new equipment adopting scheme A (as shown by b1 and b3 in Figure 7, or b1 and b4 in Figure 7, or b1 and b5 in Figure 7). In other words, compared with schemes B, C, and D, scheme E can reduce the throughput of the new equipment, thereby reducing the impact of low-latency service transmission on the channel access of traditional equipment and providing better fairness.

[0167] Figure 9 is a schematic diagram of the average latency of the new equipment. As shown in the right half of Figure 9, when the traffic volume of low-latency services is relatively large (as shown by the horizontal axis of Figure 9 at 0.05, 0.1, 0.5 or 1.0), for each traffic volume (for example, at the horizontal axis of Figure 9 at 0.1), compared with the new equipment using schemes A, B and C, when the new equipment uses scheme E, the average latency of the new equipment is significantly reduced (as shown by c1 and c3 in Figure 9, or c2 and c3 in Figure 9). In other words, compared with schemes A, B and C, scheme E can significantly reduce the channel access latency of the new equipment and improve the transmission efficiency of low-latency services.

[0168] Figure 10 is a schematic diagram of the latency of the new device at the 0.999th percentile. As shown in the right half of Figure 10, when the traffic volume of low-latency services is relatively large (as shown by the horizontal axis at 0.1, 0.5, or 1.0 in Figure 10), for each traffic volume (for example, at the horizontal axis at 0.1 in Figure 10), compared with the new device using schemes A, B, and C, when the new device uses scheme E, the latency of the new device at the 0.999th percentile is significantly reduced (as shown by d1 and d3 in Figure 10, or d2 and d3 in Figure 10). In other words, compared with schemes A, B, and C, scheme E can significantly reduce the channel access latency of the new device and improve the transmission efficiency of low-latency services.

[0169] Figure 11 is a schematic diagram of the latency of the new device at the 0.99999th percentile. As shown in the right half of Figure 11, when the traffic volume of low-latency services is relatively large (as shown by the horizontal axis at 0.1, 0.5, or 1.0 in Figure 11), for each traffic volume (for example, at the horizontal axis at 0.1 in Figure 11), compared with the new device using schemes A, B, and C, when the new device uses scheme E, the latency of the new device at the 0.99999th percentile is significantly reduced (as shown by e1 and e4 in Figure 11, or e2 and e4 in Figure 11, or e3 and e4 in Figure 11). In other words, compared with schemes A, B, and C, scheme E can significantly reduce the channel access latency of the new device and improve the transmission efficiency of low-latency services.

[0170] Figure 12 is a schematic diagram of the packet loss rate (PLR) of the new equipment. As shown in the right half of Figure 12, when the traffic volume of low-latency services is relatively large (as shown by the horizontal axis of Figure 12 at 0.05, 0.1, 0.5 or 1.0), for each traffic volume (for example, at the horizontal axis of Figure 12 at 0.05), compared with the new equipment using schemes A, B and C, when the new equipment uses scheme E, the packet loss rate is significantly reduced (as shown by f1 and f4 in Figure 12, or f2 and f4 in Figure 12, or f3 and f4 in Figure 12), and f4 is close to 0. That is to say, compared with schemes A, B and C, scheme E can significantly reduce the packet loss rate of the new equipment and improve the transmission reliability of low-latency services.

[0171] It is understood that, in order to achieve the functions in the above embodiments, the base station and terminal include hardware structures and / or software modules corresponding to perform each function. Those skilled in the art should readily recognize that, based on the units and method steps described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0172] Figures 13 and 14 are schematic diagrams of the communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of the terminal or base station in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of this application, the communication device can be a first station, or it can be a module (such as a chip) applied to the first station.

[0173] As shown in Figure 13, the communication device 2000 includes a processing unit 2010 and a transceiver unit 2020. The communication device 2000 is used to implement the functions of the first station in the method embodiment shown in Figure 6 above.

[0174] When the communication device 2000 is used to implement the function of the first station in the method embodiment shown in FIG6: the processing unit 2010 is used to: perform a first backoff on the channel; the transceiver unit 2020 is used to: send a first delay signal on the channel when the value of the backoff counter of the first station becomes 0.

[0175] For a detailed description of the functions performed by the processing unit 2010 and the transceiver unit 2020, please refer to the relevant description in the method shown in Figure 6.

[0176] As shown in Figure 14, the communication device 3000 includes a processor 3010 and an interface circuit 3020. The processor 3010 and the interface circuit 3020 are coupled together. It is understood that the interface circuit 3020 can be a transceiver or an input / output interface. Optionally, the communication device 3000 may also include a memory 3030 for storing instructions executed by the processor 3010, or storing input data required by the processor 3010 to execute instructions, or storing data generated after the processor 3010 executes instructions. Sometimes, the interface circuit 3020 can also be understood as part of the processor 3010, in which case the communication device 3000 includes the processor 3010.

[0177] When the communication device 3000 is used to implement the method shown in FIG6, the processor 3010 is used to implement the function of the processing unit 2010, and the interface circuit 3020 is used to implement the function of the transceiver unit 2020.

[0178] When the aforementioned communication device is a chip applied to the first site, the chip implements the functions of the first site in the above method embodiments. The chip receiving information can be understood as the information being first received by other modules (such as an RF module or antenna) in the first site, and then sent to the chip by these modules. The chip sending information can be understood as the information being first sent to other modules (such as an RF module or antenna) in the first site, and then sent by these modules.

[0179] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0180] The method steps in the embodiments of this application can be implemented in hardware or in software instructions executable by a processor. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. The storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a base station or terminal. The processor and storage medium can also exist as discrete components in a base station or terminal.

[0181] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0182] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0183] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship. "Including at least one of A, B, and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B, and C.

[0184] In this application, descriptions such as "when," "under the circumstances," "if," and "if" all refer to the device making corresponding actions under certain objective circumstances. They are not time-limited, nor do they require the device to make a judgment action during implementation, nor do they imply any other limitations.

[0185] It should be understood that in the various embodiments of this application, the terms "first," "second," and various numerical designations are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above processes does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

[0186] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0187] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0188] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0189] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0190] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0191] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0192] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method of channel access, the method comprising: Applied to the first site, including: Perform the first backoff on the channel; When the backoff counter value of the first station becomes 0, a first delay signal is transmitted on the channel.

2. The method of claim 1, wherein, The first delay signal is used to delay the channel access of the second site.

3. The method according to claim 1 or 2, characterized in that, After sending the first delayed signal, the method further includes: A second backoff is performed on the channel; When the backoff counter value of the first station becomes 0, the first radio frame is transmitted on the channel.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: When the first wireless frame fails to be transmitted, a second delay signal is sent on the channel; A third backoff is performed on the channel after the second delayed signal is sent; When the backoff counter value of the first station becomes 0, part or all of the first radio frame is retransmitted on the channel.

5. The method of claim 4, wherein, The method further includes: If no acknowledgment frame for the first wireless frame is received within a preset time period after the first wireless frame is sent, it is determined that the first wireless frame was not successfully transmitted.

6. The method according to claim 4 or 5, characterized in that, The initial value of the backoff counter when the first station performs the second backoff is determined based on the second contention window, and the initial value of the backoff counter when the first station performs the third backoff is determined based on the third contention window, wherein the third contention window is greater than or equal to the second contention window.

7. The method according to any one of claims 1 to 3, characterized in that, The method further includes: When the first radio frame is successfully transmitted, a fourth backoff is performed on the channel; When the backoff counter value of the first station becomes 0, a third delayed signal is transmitted on the channel.

8. The method of claim 7, wherein, After sending the third delayed signal, the method further includes: A fifth backoff is performed on the channel; When the backoff counter value of the first station becomes 0, a second radio frame is transmitted on the channel.

9. The method according to claim 7 or 8, characterized in that, The initial value of the backoff counter when the first station performs the first backoff is determined based on the first contention window, and the initial value of the backoff counter when the first station performs the fourth backoff is determined based on the fourth contention window, wherein the fourth contention window is larger than the first contention window.

10. The method according to any one of claims 7 to 9, characterized in that, The initial value of the backoff counter when the first station performs the fourth backoff is determined based on the fourth contention window, which is: CW4 = x * CWmin + (x - 1). Wherein, CW4 represents the fourth competition window, CWmin represents the minimum value of the competition window, and x is a positive integer.

11. The method according to any one of claims 7 to 9, characterized in that, The initial value of the backoff counter when the first station performs the fourth backoff is determined based on the fourth contention window, which is determined according to the number of retransmissions before the first station last obtained a transmission opportunity.

12. The method of claim 11, wherein, The fourth competition window is: CW4=CWmin+N*(CWmin+1); or, CW4=CWmin+(N+1)*(CWmin+1); or, CW4=CWmin+CW(0)+CW(1)+CW(2)+...+CW(N); Wherein, CW4 represents the fourth contention window, CWmin represents the minimum value of the contention window, N represents the number of retransmissions before the first station obtains a transmission opportunity, CW(i+1)=2*CW(i)+1, CW(0)=CWmin, i=0,1,2,…,N-1, and N is a positive integer.

13. The method according to any one of claims 8 to 12, characterized in that, The initial value of the backoff counter when the first station performs the second backoff is determined based on the second contention window, and the initial value of the backoff counter when the first station performs the fifth backoff is determined based on the fifth contention window, wherein the fifth contention window is equal to the second contention window.

14. The method according to any one of claims 1 to 13, characterized in that, The initial value of the backoff counter when the first station performs the first backoff is determined based on the first contention window, and the initial value of the backoff counter when the first station performs the second backoff is determined based on the second contention window. The first contention window is equal to the minimum value of the contention window, and the second contention window is greater than or equal to the minimum value of the contention window.

15. A communications device, characterized by include: Units for performing the methods described in any one of claims 1 to 14.

16. A communications device, characterized by include: A processor coupled to a memory for storing a computer program, the processor for executing the computer program stored in the memory to cause the apparatus to perform the method as described in any one of claims 1 to 14.

17. A computer readable storage medium characterized by The storage medium stores a computer program or instructions, which, when executed by a communication device, implement the method as described in any one of claims 1 to 14.

18. A computer program product, characterised in that, Includes a computer program that, when run, implements the method as described in any one of claims 1 to 14.

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