Channel access method and apparatus

Abstract

The present application provides a channel access method and apparatus, which can shorten the channel access time of a device and improving the channel competition efficiency. The method comprises: a first device executes a backoff procedure; and when the numerical value of a backoff counter is zero, the first device sends a first frame to a second device, wherein a protocol data unit (PPDU) format of the first frame is a set format, a frame control field, a transmission duration field, an address field, and a scrambling seed comprised in the first frame are all set values, and the first frame is used for transferring the channel scheduling right to the second device.

Description

Channel access method and device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 28, 2023, with application number 202311294091.X and application name “Channel Access Method and Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communications, and in particular to a channel access method and device. Background Art

[0003] In a wireless local area network (WLAN), stations (STAs) with data to send compete for the channel through the carrier sense multiple access (CSMA) / collision avoidance (CA) mechanism to obtain the right to send data.

[0004] To improve channel efficiency, one existing design requires that any station in the basic service set (BSS) that successfully contends for a channel transfer channel scheduling rights to the access point (AP) via a frame (such as a request to send (RTS) frame), which then schedules the channel. However, for multiple stations executing a backoff process based on the CSMA / CA mechanism, if their backoff counters simultaneously reach zero, the RTS frames sent simultaneously by multiple stations will fail due to collisions. The colliding stations may then reselect the same backoff counter value, causing continued collisions and long delays.

[0005] Summary of the Invention

[0006] The present application provides a channel access method and apparatus, which are beneficial to shortening the time it takes for a device to access a channel and improving channel competition efficiency.

[0007] In a first aspect, a channel access method is provided, including: a first device executes a backoff process; when the value of a backoff counter is zero, a first frame is sent to a second device, the protocol data unit PPDU format of the first frame is a set format, and the frame control field, transmission duration field, address field and scrambling code seed included in the first frame are all set values, and the first frame is used to transfer the channel scheduling right to the second device.

[0008] In an embodiment of the present application, when the first device determines that the value of the backoff counter is zero, it sends a first frame to the second device, in which the PPDU format is a set format, and the frame type field, transmission duration field, address field, and scrambling code seed are all set values. Since all information contained in the first frame is pre-set and does not change with different devices sending the first frame, when there are multiple devices sending the first frame to the second device at the same time, for the second device, receiving multiple first frames is equivalent to receiving multipath signals of the first frame sent by the same device. After receiving the first frame, the second device becomes a transmission opportunity (TXOP) holder and has the right to schedule the channel. It can send data to other devices or schedule other devices to send uplink data through trigger frames. According to the method provided in the embodiment of the present application, when the first device successfully competes for the channel (i.e., the backoff counter value returns to zero), the first device transfers the channel scheduling right to the second device through a first frame with a fixed format and content. Since the first frame does not change with different sending devices, when there are multiple devices competing and successfully sending the first frame at the same time, the second device can still normally receive multiple first frames sent by multiple devices, avoiding the delay caused by each device reselecting the competition window for backoff after the collision of the first frame, which is beneficial to shortening the time for the second device to access the channel and improving the efficiency of channel competition.

[0009] It should be understood that the first device and the second device belong to the same BSS. After receiving the first frame, the second device has the scheduling right of the channel that the first device has competed for. The second device can send data or trigger frames to any device in the BSS. The device that receives the data or trigger frame can be the first device or other devices in the BSS. This application does not limit this.

[0010] It should also be understood that the PPDU format included in the first frame described in the embodiment of the present application is a set format, and the frame control field, transmission duration field, address field and scrambling code seed are all set values, which means that the format and content of the first frame are pre-set, and the PPDU format, frame control field, transmission duration field, address field and scrambling code seed in the first frame sent by any two devices are the same.

[0011] In combination with the first aspect, in some implementations of the first aspect, the address field includes a receiving address field and a sending address field, the receiving address field is the MAC address of the second device, and the sending address field is a set MAC address.

[0012] In existing standards, for frames requiring a response, the receiving address field is the MAC address of the device receiving the frame, and the transmitting address field is the MAC address of the device transmitting the frame. In the first frame provided by this application, the receiving address field is the MAC address of the second device, and the transmitting address field is set to a predefined MAC address. Based on the difference in the transmitting address setting compared to the prior art, the second device can identify this frame as the first frame to transfer channel scheduling rights.

[0013] Optionally, the MAC address set in the sending address field can be any broadcast address, multicast address, or address of other devices that do not interact with the second device, and this application does not make specific limitations on this.

[0014] In combination with the first aspect, in certain implementations of the first aspect, at least one of the following fields in the frame control field is set to 1: To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field, and Protected Frame field.

[0015] It should be understood that the To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field, and Protected Frame field in the control frame in the existing standard are all set to zero. In the case where the frame type of the first frame provided in this application is a control frame, one or more designated fields of these fields that are set to zero in the prior art are set to 1 to distinguish the first frame from other existing control frames. The "designated" here refers to the agreement by the protocol. For example, the protocol stipulates that the first frame is a control frame and only the More Fragments field of the above fields included in the frame control field of the first frame is set to 1. Then, no matter which device sends the first frame, the difference between it and the existing control frame is that the More Fragments field value is 1.

[0016] In the embodiments of the present application, a reserved field in the frame control field, which is not given actual meaning in the prior art control frame, is used to identify the first frame. The second device can then identify the first frame based on this field. The method provided by the present application implicitly identifies the first frame without occupying the type field or subtype field of the frame, leaving more possibilities for defining the frame type.

[0017] In combination with the first aspect, in certain implementations of the first aspect, the first device belongs to a first group, the PPDU format of the first frame sent by different devices in the first group is the same, and the following fields included in the first frame sent by different devices in the first group have the same values: frame control field, transmission duration field, address field, and scrambling code seed.

[0018] Optionally, the first group may include all devices in the BSS where the first device is located, or may only include some devices in the BSS where the first device is located, which is not limited in this application.

[0019] Optionally, the first group may be devices with the same service and / or the same service period, which is not limited in this application.

[0020] In the embodiment of the present application, the device with data to send in the first group can participate in the competition, or it can be agreed that the device can participate in the competition regardless of whether it has data to send, and the channel scheduling right is handed over to the second device after the channel competition is successful, so as to improve the success rate of the first group channel competition. When the backoff counters of multiple devices in the first group back off to zero at the same time, the multiple devices simultaneously send the first frame to the second device. The PPDU format of the first frame sent by the multiple devices is the same format, and the frame control field, transmission duration field, address field and scrambling code seed are all the same value. Therefore, the second device is equivalent to receiving the multipath signal of the first frame, and no collision will occur. Devices whose backoff counters back off to zero at the same time do not need to reselect the backoff time to continue competing, which is conducive to avoiding the delay caused by the collision. The second device can obtain the channel scheduling right in time, thereby improving the efficiency of the channel competition.

[0021] In combination with the first aspect, in some implementations of the first aspect, the method further includes: the first device receiving first configuration information from the second device, where the first configuration information is used to indicate that the first device belongs to the first group.

[0022] In combination with the first aspect, in some implementations of the first aspect, the method also includes: the first device receives group indication information from the second device, and the group indication information includes a group identifier of at least one group; the first device sends a first request to the second device based on the group indication information, and the first request is used to request to join the first group of the at least one group; the first device receives a first response from the second device to the first request.

[0023] It should be understood that when the above-mentioned first response is a response to the success of the first request, it means that the second device agrees that the first device joins the first group.

[0024] In combination with the first aspect, in some implementations of the first aspect, the first group is grouped through a broadcast target wake-up time B-TWT mechanism or a restricted target wake-up time R-TWT mechanism.

[0025] In combination with the first aspect, in some implementations of the first aspect, the method also includes: the first device receives second configuration information, and the second configuration information is used to configure the first service period; the first device executes the backoff process, including: the first device executes the backoff process within the first service period.

[0026] It should be understood that the first service period is a period during which the first device is allowed to compete for the channel. When the first service period arrives, the first device can participate in the channel competition to assist the second device in obtaining the channel scheduling right as soon as possible.

[0027] With reference to the first aspect, in certain implementations of the first aspect, the first device is an access point AP or a non-access point station non-AP STA.

[0028] In combination with the first aspect, in some implementations of the first aspect, the first frame is a request to send RTS frame or a clear to send CTS frame.

[0029] The first frame provided in the embodiment of the present application has a type field value that corresponds to RTS or CTS, but the reserved field, address field and transmission duration field in its frame control field are partially or completely different from those in the prior art, in order to allow the second device to recognize the first frame.

[0030] With reference to the first aspect, in certain implementations of the first aspect, the PPDU format is a non-high-throughput non-HT PPDU or a non-high-throughput duplicate non-HT PPDU.

[0031] It should be understood that the first frame includes a physical layer (PHY) structure and a MAC layer structure. The PPDU format provided in the embodiment of the present application is a limitation on the format of the physical layer of the first frame. The PPDU format is the encapsulation format of the frame generated by the physical layer to the MAC layer.

[0032] On the second aspect, the present application provides a channel access method, including: a second device receives a first frame, the protocol data unit PPDU format of the first frame is a set format, the frame control field, transmission duration field, address field and scrambling code seed included in the first frame are all set values, and the first frame is used to transfer the channel scheduling right to the second device; the second device sends data or a trigger frame, and the trigger frame is used to schedule uplink data.

[0033] In combination with the second aspect, in certain implementations of the second aspect, the method further includes: the second device receives a second frame sent by the third device, and the PPDU format, frame control field, transmission duration field, address field and scrambling code seed of the second frame are the same as those of the first frame.

[0034] In combination with the second aspect, in some implementations of the second aspect, the address field includes a receiving address field and a sending address field, the receiving address field is the media access control MAC address of the second device, and the sending address field is the set MAC address.

[0035] In combination with the second aspect, in certain implementations of the second aspect, at least one of the following fields in the frame control field is set to 1: To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field, and Protected Frame field.

[0036] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the second device sending first configuration information to the first device, where the first configuration information is used to indicate that the first device belongs to a first group.

[0037] In combination with the second aspect, in some implementations of the second aspect, the method also includes: the second device sends group indication information, the group indication information includes a group identifier of at least one group; the second device receives a first request from the first device, the first request is used to request to join a first group in the at least one group; the second device sends a first response to the first request to the first device.

[0038] In combination with the second aspect, in some implementations of the second aspect, the first group is grouped through a broadcast target wake-up time B-TWT mechanism or a restricted target wake-up time R-TWT mechanism.

[0039] In combination with the second aspect, in certain implementations of the second aspect, the first device belongs to a first group, the PPDU format of the first frame sent by different devices in the first group is the same, and the following fields included in the first frame sent by different devices in the first group have the same values: frame control field, transmission duration field, address field, and scrambling code seed.

[0040] In combination with the second aspect, in some implementations of the second aspect, the method further includes: the second device sends second configuration information to the first device, the second configuration information is used to configure the first service period; the first device performs a backoff process within the first service period.

[0041] In combination with the second aspect, in some implementations of the second aspect, the second device is an access point AP or a non-access point station non-AP STA.

[0042] In combination with the second aspect, in some implementations of the second aspect, the first frame is a request to send RTS frame or a clear to send CTS frame.

[0043] In combination with the second aspect, in certain implementations of the second aspect, the PPDU format is a non-high-throughput non-HT PPDU or a non-high-throughput duplicate non-HT duplicate PPDU.

[0044] In the third aspect, the present application also provides a channel access method, which is applied to a first group including a first device, a second device and a third device, and the method includes: the first device executes a backoff process; when the value of the backoff counter is zero, the first device sends a first frame to the second device, and the protocol data unit PPDU format of the first frame is a set format, and the frame control field, transmission duration field, address field and scrambling code seed included in the first frame are all set values, and the first frame is used to transfer the channel scheduling right to the second device; the third device executes a backoff process; when the value of the backoff counter is zero, the third device sends a second frame to the second device, and the PPDU format, frame control field, transmission duration field, address field and scrambling code seed in the second frame are the same as those of the first frame; the second device receives the first frame and the second frame; the second device sends data or a trigger frame, and the trigger frame is used to schedule uplink data.

[0045] According to the method provided by the embodiment of the present application, the frames sent by the first device and the third device for transferring the channel scheduling right when the backoff counter backs off to zero are exactly the same frames. When the backoff counters of the first device and the second device back off to zero at the same time, the first frame sent by the first device will not collide with the second frame sent by the third device. For the first device and the third device, the channel scheduling right can be transferred to the second device without further backing off. For the second device, it can access the channel in a timely manner, thereby improving the efficiency of channel access.

[0046] In combination with the third aspect, in certain implementations of the third aspect, the first frame is a frame that requires a response, the address field includes a receiving address field and a sending address field, the receiving address field is the media access control MAC address of the second device, and the sending address field is a set MAC address.

[0047] In combination with the third aspect, in certain implementations of the third aspect, at least one of the following fields in the frame control field is set to 1: To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field, and Protected Frame field.

[0048] In combination with the third aspect, in some implementations of the third aspect, the method further includes: the second device sending first configuration information to the first device, where the first configuration information is used to indicate that the first device belongs to a first group.

[0049] In combination with the third aspect, in some implementations of the third aspect, the method also includes: the second device sends group indication information, the group indication information includes a group identifier of at least one group; the second device receives a first request from the first device, the first request is used to request to join a first group in the at least one group; the second device sends a first response to the first request to the first device.

[0050] In combination with the third aspect, in certain implementations of the third aspect, the first group is grouped through a broadcast target wake-up time B-TWT mechanism or a restricted target wake-up time R-TWT mechanism.

[0051] In combination with the third aspect, in certain implementations of the third aspect, the method also includes: the second device sends second configuration information to the first device, and the second configuration information is used to configure the first service period; the first device executes the backoff process, including: the first device executes the backoff process within the first service period.

[0052] In combination with the third aspect, in some implementations of the third aspect, the first device and the third device are non-access point stations (non-AP STAs).

[0053] In combination with the third aspect, in some implementations of the third aspect, the second device is an access point AP.

[0054] In combination with the third aspect, in certain implementations of the third aspect, the first frame is a request to send RTS frame or a clear to send CTS frame.

[0055] In combination with the third aspect, in certain implementations of the third aspect, the PPDU format is a non-high-throughput non-HT PPDU or a non-high-throughput duplicate non-HT duplicate PPDU.

[0056] In a fourth aspect, the present application also provides a channel access method, including: a first device executes a backoff process; when the value of the backoff counter is zero, a first frame is sent to a second device, wherein the first device belongs to a first group, and the first frames sent by different devices in the first group are the same.

[0057] In a fifth aspect, a channel access device is provided, which includes a module for executing the method in any possible implementation of the first aspect, the second aspect or the fourth aspect.

[0058] In a sixth aspect, a communication system is provided, comprising a first device, a second device and a third device, for executing the method in any possible implementation manner of the third aspect above.

[0059] In a seventh aspect, the present application provides another channel access device, comprising a processor coupled to a memory and configured to execute instructions in the memory to implement the method of any possible implementation of the first, second, or fourth aspects described above. Optionally, the device further comprises a memory. Optionally, the device further comprises a communication interface, the processor coupled to the communication interface.

[0060] In one implementation, the apparatus is a terminal device. When the apparatus is a terminal device, the communication interface may be a transceiver, or an input / output interface.

[0061] In another implementation, the device is a chip configured in a terminal device. When the device is a chip configured in a terminal device, the communication interface may be an input / output interface.

[0062] In an eighth aspect, a processor is provided, comprising: an input circuit, an output circuit, and a processing circuit. The processing circuit is configured to receive a signal through the input circuit and transmit a signal through the output circuit, so that the processor executes the method of any possible implementation of the first, second, or fourth aspects.

[0063] In a specific implementation process, the processor may be a chip, the input circuit may be an input pin, the output circuit may be an output pin, and the processing circuit may be a transistor, a gate circuit, a trigger, or various logic circuits. The input signal received by the input circuit may be, for example, but not limited to, received and input by a receiver, and the signal output by the output circuit may be, for example, but not limited to, output to and transmitted by a transmitter. The input circuit and the output circuit may be the same circuit, which functions as an input circuit and an output circuit at different times. The embodiments of the present application do not limit the specific implementation of the processor and various circuits.

[0064] In a ninth aspect, a processing device is provided, comprising a processor and a memory. The processor is configured to read instructions stored in the memory and to receive signals via a receiver and transmit signals via a transmitter to execute the method of any possible implementation of the first, second, or fourth aspects.

[0065] Optionally, there are one or more processors and one or more memories.

[0066] Optionally, the memory may be integrated with the processor, or the memory may be provided separately from the processor.

[0067] In the specific implementation process, the memory can be a non-transitory memory, such as a read-only memory (ROM), which can be integrated with the processor on the same chip or set on different chips. This application does not limit the type of memory and the setting method of the memory and the processor.

[0068] It should be understood that related data interaction processes, such as sending indication information, can be processes for outputting indication information from a processor, and receiving capability information can be processes for receiving input capability information from a processor. Specifically, the output data of the processor can be output to a transmitter, and the input data received by the processor can come from a receiver. The transmitter and receiver can be collectively referred to as a transceiver.

[0069] The processing device in the above-mentioned ninth aspect can be a chip. The processor can be implemented by hardware or by software. When implemented by hardware, the processor can be a logic circuit, an integrated circuit, etc.; when implemented by software, the processor can be a general-purpose processor, which is implemented by reading the software code stored in the memory. The memory can be integrated in the processor or can be located outside the processor and exist independently.

[0070] In the tenth aspect, a computer program product is provided, which includes: a computer program (also referred to as code, or instructions), which, when executed, enables a computer to execute a method in any possible implementation of the first, second or fourth aspects above.

[0071] In the eleventh aspect, a computer-readable storage medium is provided, which stores a computer program (also referred to as code, or instructions) which, when run on a computer, enables the computer to execute a method in any possible implementation of the first, second or fourth aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] FIG1 is a schematic diagram of a communication system applicable to an embodiment of the present application;

[0073] FIG2 is a schematic diagram of an existing random backoff mechanism;

[0074] FIG3 is a schematic flow chart of a channel access method provided by the present application;

[0075] FIG4 is a schematic diagram of a frame structure of a control frame provided in this application:

[0076] FIG5 is a schematic diagram of the frame structure of another control frame provided in this application:

[0077] FIG6 is a schematic diagram of a frame control field structure provided by the present application;

[0078] FIG7 is a schematic diagram of a grouping mechanism provided by this application;

[0079] FIG8 is a schematic diagram of an implementation process of a channel access method provided by the present application;

[0080] FIG9 is a schematic diagram of an implementation process of another channel access method provided by the present application;

[0081] FIG10 is a schematic block diagram of a channel access device provided in an embodiment of the present application;

[0082] FIG11 is a schematic block diagram of another channel access device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0083] The technical solution in this application will be described below with reference to the accompanying drawings.

[0084] In the embodiments of the present application, terms such as "first" and "second" are used to distinguish identical or similar items with basically the same functions and effects. For example, the first numerical value and the second numerical value are merely used to distinguish different numerical values, and do not limit their order. Those skilled in the art can understand that terms such as "first" and "second" do not limit the quantity and execution order, and terms such as "first" and "second" do not necessarily mean different.

[0085] It should be noted that in the embodiments of the present application, words such as "exemplarily" or "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design solution described as "exemplarily" or "for example" in the present application should not be construed as more preferred or more advantageous than other embodiments or design solutions. Rather, the use of words such as "exemplarily" or "for example" aims to present relevant concepts in a specific manner.

[0086] In the embodiments of the present application, "at least one" means one or more, and "multiple" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one (item)" or its similar expression refers to any combination of these items, including any combination of single item (item) or multiple items (items). For example, at least one (item) of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple.

[0087] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as: wireless local area network (WLAN) communication system, general packet radio service (GPRS), long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD), universal mobile telecommunication system (UMTS), worldwide interoperability for microwave access (WiMAX) communication system, fifth generation (5G) system or new radio (NR), etc.

[0088] The following is an exemplary description, taking a WLAN system as an example to describe the application scenario and method of the embodiment of the present application.

[0089] Specifically, the embodiments of the present application can be applied to wireless local area networks (WLANs), and can be applied to any of the IEEE 802.11 series protocols currently used by WLANs, and are particularly applicable to WLAN systems that utilize the 802.11be standard, the 802.11bn standard, and subsequent improved standards thereof. A WLAN may include one or more basic service sets (BSSs), and network nodes in the BSSs may include access points (APs) and stations (STAs).

[0090] Specifically, the station (STA) in the embodiments of the present application may also be referred to as a system, user unit, access terminal, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, user device or user equipment (UE). The STA may be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless local area network (e.g., Wi-Fi) communication function, a wearable device, a computing device or other processing device connected to a wireless modem. Among them, STA products are generally terminal products that support the IEEE 802.11 series of standards, such as mobile phones, laptops, etc. STAs can have a single antenna or multiple antennas, and can be devices with more than two antennas. Exemplarily, a STA may include a physical layer (PHY) processing circuit and a media access control (MAC) processing circuit. The physical layer processing circuit may be used to process physical layer signals, and the MAC layer processing circuit may be used to process MAC layer signals.

[0091] The access point (AP) in the embodiment of the present application can be used to communicate with STAs through a wireless local area network and transmit data from the STA to the network side, or transmit data from the network side to the STA. The AP can also be called a wireless access point or hotspot, etc. The AP is an access point for mobile users to enter the wired network. It is mainly deployed in homes, buildings, and campuses, and can also be deployed outdoors. The AP is equivalent to a bridge connecting the wired network and the wireless network. Its main function is to connect various wireless network clients together and then connect the wireless network to the Ethernet. Specifically, the AP can be a terminal device or network device with a wireless fidelity (Wi-Fi) chip. Optionally, the AP can be a device that supports multiple WLAN standards such as 802.11. Specifically, the AP can be multi-antenna or single-antenna. Exemplarily, the AP may include a physical layer (PHY) processing circuit and a media access control (MAC) processing circuit. The physical layer processing circuit can be used to process physical layer signals, and the MAC layer processing circuit can be used to process MAC layer signals.

[0092] Figure 1 shows a schematic diagram of an application scenario according to an embodiment of the present application. The scenario system shown in Figure 1 can be a WLAN system. The WLAN system in Figure 1 can include an AP and one or more STAs. Figure 1 uses an AP (AP 1) and three STAs (STA 1, STA 2, and STA 3) as an example. Wireless communication between the AP and the STAs, and between the STAs, can be carried out using various standards.

[0093] Specifically, wireless communication between the AP and the STA can be carried out using single-user multiple-input multiple-output (SU-MIMO) technology or multi-user multiple-input multiple-output (MU-MIMO) technology. In an embodiment of the present application, each STA is equipped with one or more antennas. Each AP supports multi-site parallel uplink transmission. Specifically, the STA or AP includes an antenna with an adjustable beam, a radio frequency (RF) channel corresponding to the antenna, a signal processing module, a protocol module, and the like.

[0094] The connection between the antenna and the RF channel can be either a fixed or switchable connection. The RF channel is connected to the signal processing module to perform digital-to-analog or analog-to-digital conversion and transmit and receive signal processing. The signal processing module can generate reference signals for measurement and receive reference signals to estimate signal strength, channel quality, or channel coefficients. The signal processing module is also connected to a local clock source to modulate the signal to the target frequency band or demodulate it. The local clock source also provides a time reference for when to send a specific physical layer (PHY) protocol data unit (PPDU). The signal processing module can trigger the transmission of a specific PPDU at a specified time. The signal processing module is also connected to the protocol module to perform packet encapsulation and decapsulation, and execute the packet transmission and reception sequence specified by the protocol, including sending training frames, receiving training frames, and replying response frames. The signal processing module or protocol module can also instruct the antenna to use the beam for transmission or reception.

[0095] Optionally, the STA or AP in the embodiment of the present application may further include an external interface module, but the embodiment of the present application is not limited thereto.

[0096] Below, some concepts or terms involved in this application are briefly introduced.

[0097] 1. Basic service set (BSS)

[0098] The Basic Service Set (BSS) is the fundamental component of an 802.11 local area network (LAN). A BSS consists of an access point (AP) and several stations (STAs). All STAs can communicate directly within the BSS, but when communicating with STAs outside the BSS, they must go through the BSS's AP.

[0099] 2. Network allocation vector (NAV)

[0100] Virtual carrier sense (VCS) is a type of carrier sensing that uses control information to determine channel conditions, rather than actually detecting the physical channel. VCS uses the relevant information carried in the media access control (MAC) frame to perform logical predictions. Each frame carries the transmission duration of the next frame from the transmitting device, and associated devices use this duration to predict channel occupancy. If a device does not detect the duration, for example, if the frame's duration field has already been transmitted when it monitors the carrier, the device can only rely on physical layer detection.

[0101] Virtual carrier sensing can be implemented using the Network Allocation Vector (NAV). The NAV is essentially a countdown timer that decreases over time. When the countdown reaches 0, the medium is considered idle. Therefore, virtual carrier sensing technology sets and updates the NAV timer at appropriate times and with appropriate values. For example, when a device receives a frame, if the frame is not addressed to the device, the device can update the NAV based on the transmission duration field in the received frame. If the frame is addressed to the device, indicating that it is the receiving device, the NAV cannot be updated.

[0102] 3. Distributed coordination function (DCF)

[0103] DCF is a mandatory technology for preventing collisions in wireless local area networks based on the IEEE 802.11 standard. It is a medium access control (MAC) sublayer technology used in areas that adopt Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA).

[0104] According to the basic technical process of DCF, before sending data or management frames, device 1 needs to call the carrier sensing (CS) mechanism to determine whether the channel status is idle or busy. It should be understood that device 1 can be a STA or an AP.

[0105] When a busy channel is detected, device 1 postpones channel access by a specific time. This specific time is defined in two ways: First, when device 1 detects a frame but fails to receive it, the specific time is the extended interframe space (EIFS), where EIFS = aSIFSTime + AckTxTime + DIFS. Second, the specific time is the distributed coordination function interframe space (DIFS), where DIFS = aSIFSTime + 2*aSlotTime. EIFS = aSIFSTime + AckTxTime + DIFS, where AckTxTime is the transmission duration of an acknowledgment (ACK) frame. Typically, a short interframe space (SIFS) duration (aSIFSTime) is 16 microseconds, and a slot duration (aSlotTime) is 9 microseconds. The specific values ​​of aSIFSTime and aSlotTime may vary depending on the spectrum and protocol, and this application does not limit these values.

[0106] When the channel is detected to be idle for DIFS or EIFS (DIFS is used as an example in the following description), the backoff counter value selected by device 1 is reduced by 1 every time the channel is idle for one time slot. When the backoff counter value is reduced to 0, data is sent.

[0107] Figure 2 illustrates a random backoff mechanism. As shown in Figure 2, after detecting that the channel is busy, the transmitting device waits for the channel to become idle for a DIFS (or EIFS, using DIFS as an example in Figure 2). It then randomly selects a value within the contention window (CW) as the backoff counter value and begins backoff. When the backoff counter reaches zero, it sends a data frame containing the NAV information. Upon receiving this data frame, other devices update their own NAVs based on the duration field in the data frame, indicating that the channel is busy during this period and that they need to delay if they have data to send. The receiving device correctly receives the data frame and waits for SIFS before sending an ACK frame to the transmitting device. Once the ACK frame is sent, the channel becomes idle. After waiting for the DIFS, other devices that need to send data begin contention for the channel using the backoff algorithm. The device whose backoff counter first reaches 0 successfully contends for the channel and begins sending data frames.

[0108] 4. Enhanced distributed channel access (EDCA)

[0109] EDCA is derived from DCF. In DCF, a device has only one contention queue, and all data to be sent is cached in the same queue. In EDCA, a device supports four access categories to distinguish data of different priorities. Each access category maintains an independent set of channel contention parameters. The four different access categories are AC_VO (Voice), AC_VI (Video), AC_BE (Best Effort), and AC_BK (Background), from high to low priority. AC_VO indicates that the access type (or access type) is voice (voice) flow, AC_VI indicates that the access type is video (video) flow, AC_BE indicates that the access type is best effort (best effort) flow, and AC_BK indicates that the access type is background (background) flow.

[0110] The random backoff process for each access category (AC) no longer waits for DIFS, but instead waits for the arbitration interframe space (AIFS). AIFS[AC] = AIFSN[AC] * aSlotTime + aSIFSTime, where the arbitration interframe spacing number (AIFSN) is the AIFS number. AIFSN is determined by the access type; a larger value indicates a longer idle wait time and a lower priority. Each AC also has a different minimum contention window (CWmin) and maximum contention window (CWmax). High-priority access categories can be assigned smaller AIFSN, CWmin, and CWmax parameters, while low-priority access categories can be assigned larger AIFSN, CWmin, and CWmax parameters. This increases the transmission opportunities for high-priority services and reduces the transmission opportunities for low-priority services. Optionally, the minimum value of AIFSN is 2.

[0111] An existing design is that multiple devices compete for channels through DCF or EDCA. Device 1, whose backoff counter value backs off to 0 (also known as successful competition), transfers the channel to the target device through a frame (for example, an RTS frame). The target device (for example, an AP) centrally schedules the uplink or downlink transmission of each device in the BSS to improve the channel utilization efficiency.

[0112] In this way, when only device 1 successfully competes in the BSS, the channel can be transferred to the target device in time through the above-mentioned RTS frame. However, if there are other devices that also have data to send and generate the same random backoff counter value as device 1, then the backoff counter values ​​of multiple devices that generate the same backoff counter value may back off to 0 at the same time, and then send the above-mentioned RTS frame at the same time. At this time, the RTS frames sent by each device will fail due to collision. After the transmission failure, each device will select a random number within a larger contention window for backoff. However, the device's selection of the backoff counter value is random, and there is always the possibility that multiple devices will have the same value. If device 1 continuously and repeatedly collides with other devices and continuously selects the backoff counter value for backoff, it will cause a long delay.

[0113] In view of this, the present application provides a channel access method and apparatus, in which all information contained in the first frame sent by a device when the backoff counter value is zero is pre-set and will not change due to different sending devices. Therefore, even if the backoff counters of multiple devices back off to zero at the same time and the first frame is sent to the target device at the same time, no collision will occur, which effectively avoids the delay caused by the collision, shortens the time for the target device to access the channel, and improves the channel competition efficiency.

[0114] The channel access method of the present application is described in detail below using Figures 3 to 9. The embodiments shown in this application illustrate the channel access method provided by this application from the perspective of device interaction. The specific form and quantity of each device shown therein are merely examples and should not constitute any limitation on the implementation of the method provided by this application.

[0115] FIG3 is a schematic flow chart of a channel access method 300 provided in an embodiment of the present application. The method 300 can be applied to the communication system shown in FIG1 . The method 300 specifically includes the following steps:

[0116] S301: The first device executes a backoff process.

[0117] S302. When the first device determines that the value of the backoff counter is zero, it sends a first frame to the second device. The protocol data unit PPDU format of the first frame is a set format. The frame control field, transmission duration field, address field and scrambling code seed included in the first frame are all set values. The first frame is used to transfer the channel scheduling right to the second device; correspondingly, the second device receives the first frame.

[0118] S303: The second device sends data or a trigger frame, where the trigger frame is used to schedule uplink data.

[0119] Optionally, the first device may be a STA, and the second device may be an AP, but this application does not limit this.

[0120] It should be understood that the first device and the second device belong to the same BSS. After receiving the first frame, the second device has the scheduling right of the channel that the first device has competed for. The second device can send data or trigger frames to any device in the BSS. The device that receives the data or trigger frame can be the first device or other devices in the BSS. This application does not limit this.

[0121] It should also be understood that the PPDU format included in the first frame described in the embodiment of the present application is a set format, and the frame control field, transmission duration field, address field and scrambling code seed are all set values, which means that the format and content of the first frame are pre-set, and the PPDU format, frame control field, transmission duration field, address field and scrambling code seed in the first frame sent by any two devices are the same.

[0122] In an embodiment of the present application, when the first device determines that the value of the backoff counter is zero, it sends a first frame to the second device, in which the PPDU format is a set format, and the frame type field, transmission duration field, address field, and scrambling code seed are all set values. Since all information contained in the first frame is pre-set and does not change with different devices sending the first frame, when there are multiple devices sending the first frame to the second device at the same time, for the second device, receiving multiple first frames is equivalent to receiving multipath signals of the first frame sent by the same device. After receiving the first frame, the second device becomes a transmission opportunity (TXOP) holder and has the right to schedule the channel. It can send data to other devices or schedule other devices to send uplink data through trigger frames.

[0123] Therefore, in the method provided in the embodiment of the present application, the first device transfers the channel scheduling right to the second device through the first frame with fixed format and content when the channel competition is successful (that is, the backoff counter value returns to zero). Since the first frame does not change with different sending devices, when there are multiple devices competing and successfully sending the first frame at the same time, the second device can still normally receive multiple first frames sent by multiple devices, avoiding the delay caused by each device reselecting the competition window to back off after the collision of the first frame, which is beneficial to shortening the time for the second device to access the channel and improving the efficiency of channel competition.

[0124] It should be understood that the above-mentioned "backoff process" refers to the process that the first device needs to execute after a frame (for example, a data frame or a management frame) is to be sent and / or arrives at the first service period of the first device. The backoff process includes: detecting the channel status, waiting for a specific time (DIFS or EIFS) when the channel is detected to be busy, opening the contention window and selecting the backoff counter value after detecting that the channel is idle DIFS or EIFS, and reducing the backoff counter value by 1 each time the channel is detected to be idle for a time slot after opening the contention window, etc. For example, it can be the above-mentioned DCF or EDCA process, but this application is not limited to this.

[0125] As an optional embodiment, the PPDU format of the first frame may be a non-high throughput presentation protocol data unit (non-HT PPDU) format or a non-high throughput duplicate presentation protocol data unit (non-HT duplicate PPDU) format.

[0126] It should be understood that the first frame includes a physical layer (PHY) structure and a MAC layer structure. The PPDU format provided in the embodiment of the present application is a limitation on the format of the physical layer of the first frame. The PPDU format is the encapsulation format of the frame generated by the physical layer to the MAC layer.

[0127] In a possible implementation, the scrambler seed included in the first frame does not carry bandwidth information.

[0128] In the embodiment of the present application, since the idle channel bandwidth detected by each device executing the backoff process may be different, the purpose of setting the scrambling code seed not to carry bandwidth information is to ensure that the first frame sent by any device when the backoff counter value is zero is the same frame.

[0129] In another possible implementation, the scrambling code seed included in the first frame carries set bandwidth information.

[0130] It should be understood that the set bandwidth information carried by the first frame does not necessarily match the bandwidth of the current TXOP. Therefore, regardless of whether the first frame carries bandwidth information, the second device can obtain the bandwidth of the current TXOP in the following manner:

[0131] Method 1: Detect the bandwidth of the first frame and use the bandwidth of the first frame as the bandwidth of the current TXOP.

[0132] Method 2: The bandwidth of the idle channel detected within the point coordination function interframe space (PIFS) duration before receiving the first frame is used as the bandwidth of the current TXOP.

[0133] Method 3: The bandwidth of the idle channel detected within the SIFS or PIFS duration after receiving the first frame is used as the bandwidth of the current TXOP.

[0134] Method 4: After receiving the first frame, the backoff process is executed, and the bandwidth of the idle channel detected after the backoff is completed is used as the bandwidth of the current TXOP. When the second device backs off after receiving the first frame, the value of the backoff counter can be set to zero. The reason is that after other devices other than the second device hear the first frame, they will set the network allocation vector (NAV) according to the transmission duration field in the first frame, thereby freezing the backoff counter time of other devices and temporarily not participating in the channel competition. Therefore, in order to shorten the backoff duration of the second device, the backoff counter value can be directly set to zero. However, it should be understood that the value of the backoff counter when the second device backs off after receiving the first frame can also be selected from the current existing value or any other value, and this application does not limit this.

[0135] Optionally, in the above four methods, the second device may obtain bandwidth information through packet detection or energy detection (ED). The present application does not specifically limit the bandwidth detection method of the second device.

[0136] Optionally, the first frame may be a frame requiring a response or a frame not requiring a response, which is not specifically limited in this application. The frame structure of the first frame may be as shown in FIG4 or FIG5 below.

[0137] FIG4 shows a typical frame structure of a control frame. As shown in FIG4 , the frame includes: a frame control field, a transmission duration field, a receiver address (RA) field, a transmitter address (TA) field, and a frame check sequence (FCS).

[0138] In one implementation, in the control frame of the structure shown in Figure 4, the transmitting address (RA) field identifies the MAC address of the device that sends the frame, and the receiving address (TA) field identifies the MAC address of the device that receives the frame. After receiving the frame, any device can reply a response frame to the device that sends the frame based on the MAC address set in the transmitting address (RA) field of the frame.

[0139] FIG5 shows another typical frame structure of a control frame. As shown in FIG5 , the frame includes a frame control field, a transmission duration field, a receiver address (RA) field, and a frame check sequence (FCS).

[0140] In one implementation, in the control frame of the structure shown in FIG5 , only the MAC address of the device receiving the frame is identified by the receiving address (RA) field. The control frame can generally be used as a response frame to a frame that requires a response, or as a control frame that does not require a response from the receiving device.

[0141] Figure 6 shows the structure of the frame control field applicable to Figures 4 and 5 above. As shown in Figure 6, the frame control field includes: a protocol version field, a type field, a subtype field, a to distributed system (to DS) field, a from distributed system (from DS) field, a more fragments field, a retry field, a power management field, a more data field, a protected frame field, and a high throughput control (+HTC) field.

[0142] It should be understood that the frame structures shown in Figures 4 and 5, as well as the structure of the frame control field shown in Figures 4 and 5, are all existing, common structures. The first frame provided in this application sets the frame control field, transmission duration field, and address field included in the first frame to fixed values ​​while the PPDU format is set to a set format and the scrambling code seed is a fixed value. The setting of the frame control field and address field includes the following possible implementations:

[0143] The first possible implementation method: The frame structure of the first frame can be as shown in Figure 5, and the structure of the frame control can be as shown in Figure 6. For example, the type field is used to identify whether the frame is a control frame (01), a data frame (10) or a management frame (00), and the subtype field is used to identify which subtype of the frame type identified by the field type the frame belongs to. In an embodiment of the present application, the type field and / or subtype field in the frame control of the first frame can be set to values ​​not defined in the prior art, and the remaining fields all maintain the existing settings. For example, the type field of the first frame can be set to 11, and the subtype field can be set to any value from 0000 to 1111, or the type field of the first frame can be set to 01, and the subtype field can be set to any value from 0000 to 0011 reserved for the current control frame.

[0144] Optionally, the number of bits and specific values ​​corresponding to the type field and subtype field in this application can also be other arbitrary values, and this application does not limit this.

[0145] Optionally, the present application may refer to a frame type defined by a value not defined in the prior art as a common frame, but the present application does not limit this.

[0146] A second possible implementation manner: the frame structure of the first frame is shown in FIG4 , and the structure of the frame control is shown in FIG6 .

[0147] In one case, the type field and subtype field of the first frame are technically defined values. For example, the type field is 01 and the subtype field is 1011, indicating that the type of the first frame is an RTS frame in a control frame. In existing standards, the receiving address field is the MAC address of the device receiving the frame, and the transmitting address field is the MAC address of the device transmitting the frame. In the first frame provided by this application, the receiving address field is the MAC address of the second device, and the transmitting address field is set to a preset MAC address. Based on the difference in the transmitting address setting compared to the existing technology, the second device can identify this frame as the first frame for transferring channel scheduling rights.

[0148] In another case, the type field and / or subtype field in the frame control of the first frame provided in the present application can be set to an undefined value in the prior art described in the first possible implementation method mentioned above, the receiving address field is the MAC address of the second device, and the sending address field is set to a set MAC address.

[0149] Optionally, the MAC address set in the sending address field can be any broadcast address, multicast address, or address of other devices that do not interact with the second device, and this application does not make specific limitations on this.

[0150] A third possible implementation method: the values ​​of the To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field and Protected Frame field in the existing control frame are all 0. In the first frame provided by the present application, at least one field is specified and set to 1 in the To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field and Protected Frame field in the frame control field of the first frame. The second device can identify this frame as the first frame for transferring channel scheduling rights based on the difference between the value of the specified field and the value of the field in the prior art.

[0151] Optionally, the frame type field and subtype field in the first frame can be values ​​defined in the prior art, for example, the type field is 01 and the subtype field is 1100, indicating that the type of the first frame is a CTS frame in a control frame, or, for example, the type field is 01 and the subtype field is 1011, indicating that the type of the first frame is an RTS frame in a control frame.

[0152] Optionally, the third possible implementation manner may be combined with any of the situations described in the first possible implementation manner and the second possible implementation manner, which is not limited in this application.

[0153] The setting value of the transmission duration field of the first frame provided in this application should be less than the transmission opportunity limit (TXOP limit). The setting of this value includes the following possible implementation methods:

[0154] A first possible implementation method: When the first frame is a frame that does not require a response, the value of the transmission duration field in the first frame can be set to the duration of one SIFS or one PIFS plus the duration of one MU-RTS frame transmission.

[0155] A second possible implementation method: When the first frame is a frame that requires a response, the value of the transmission duration field in the first frame can be set to the duration of a SIFS or a PIFS, plus the duration of a response frame, plus the duration of a SIFS or a PIFS and the sending duration of a MU-RTS frame.

[0156] It should be understood that the first frame is a frame sent by the first device to the second device for transferring channel scheduling rights when the backoff counter value backs off to zero, that is, when the channel competition is successful. After receiving the first frame, the second device becomes the transmission opportunity holder (TXOP holder). After receiving the first frame and waiting for a SIFS period, the second device can send an MU-RTS frame to one or more devices to reserve the channel and better protect the current channel.

[0157] It should also be understood that when setting the transmission duration of the first frame, on the one hand, it is necessary to consider avoiding channel contention initiated by some devices that are hidden nodes of the second device after the end of the first frame, resulting in a conflict with the frame to be sent by the second device after receiving the first frame. On the other hand, since the first frame can be sent by multiple devices at the same time, its coverage range may exceed the coverage range of the device that actually communicates data with the second device next, resulting in over-protection. Therefore, the value of the transmission duration field should not be too large. For example, according to the transmission duration setting method provided in the embodiment of the present application, the duration of the transmission duration field of the first frame is about 100us, which is a relatively small time value. At present, the duration of a TXOP is generally allowed to be set to 3-5ms. The method provided in the embodiment of the present application is conducive to avoiding unnecessary waiting of other devices caused by excessive channel protection time, and is conducive to improving channel utilization.

[0158] It is worth noting that although there are multiple possible implementations of the settings of the PPDU format, scrambling code seed, frame control field, address field and transmission duration field of the first frame described above, for any device sending the first frame, the PPDU format of the first frame, the frame structure of the first frame, the frame control field, transmission duration field, address field and scrambling code seed in the first frame are all protocol-specified, unique, and do not change with different sending devices.

[0159] As an optional embodiment, the first device belongs to the first group, the PPDU format of the first frame sent by different devices in the first group is the same, and the following fields included in the first frame sent by different devices in the first group have the same values: frame control field, transmission duration field, address field and scrambling code seed.

[0160] It should be understood that the devices in the first group may be devices with the same service or the same type of service, and the devices in the first group belong to the same BSS. A BSS may include one or more groups, which is not limited in this application.

[0161] As an optional embodiment, the above-mentioned first group may also include a third device, and the second device receives a second frame sent by the third device, and the PPDU format, frame control field, transmission duration field, address field and scrambling code seed in the second frame are the same as those in the first frame.

[0162] It should be understood that the second frame here is essentially the same frame as the first frame. It is named the second frame here only for the convenience of description. The similarities are reflected in the PPDU format, frame control field, transmission duration field, address field and scrambling code seed. In other words, each bit in the bit sequence of the first frame and the second frame is the same.

[0163] In a possible implementation, the first device belongs to the first group and is configured by the second device through first configuration information. The implementation includes: the first device receives the first configuration information from the second device, where the first configuration information is used to indicate that the first device belongs to the first group.

[0164] In another possible implementation, the first device belongs to the first group, which is determined after the first device interacts with the second device. The implementation method includes: the first device receives group indication information from the second device, and the group indication information includes the group identifier of at least one group; the first device sends a first request to the second device based on the group indication information, and the first request is used to request to join the first group in at least one group; the first device receives a first response from the second device to the first request.

[0165] It should be understood that when the above-mentioned first response is a response to the success of the first request, it means that the second device agrees that the first device joins the first group.

[0166] As an optional embodiment, the first group is grouped through a broadcast target wake time (B-TWT) mechanism or a restricted target wake time (R-TWT) mechanism.

[0167] Figure 7 takes the second device as an AP as an example to illustrate the process of AP establishing a group through the B-TWT mechanism or the R-TWT mechanism. As shown in Figure 7, the AP will periodically broadcast the group identifier (for example, it can be TWT ID) and the service period corresponding to the group in the Beacon frame. The STA receives the Beacon frame and sends a request to join the group to the AP. After receiving a successful response from the AP, it is considered that the STA has joined a group. If the service period corresponding to the group is the service period 1 in Figure 7, then the STA wakes up when the time corresponding to the service period 1 arrives, competes for the channel, or receives the trigger frame or data frame sent by the AP. After completing the interaction with the AP, the STA enters the sleep state and wakes up again when the next service time arrives, and so on.

[0168] It should be understood that the group to which a STA belongs and the service time of the group are not fixed. The AP broadcasts it at regular intervals, and the group identifier and service period can be different each time. The STA can join or leave the group by interacting with the AP.

[0169] As an optional embodiment, the first service period of the first device can be configured through the second configuration information, and its implementation method includes: the first device receives the second configuration information, and the second configuration information is used to configure the first service period; the first device executes the backoff process, including: the first device executes the backoff process within the first service period.

[0170] It should be understood that the first service period is a period during which the first device is allowed to compete for the channel. When the first service period arrives, the first device can participate in the channel competition to assist the second device in obtaining the channel scheduling right as soon as possible.

[0171] Optionally, the first device provided in the embodiment of the present application may be a STA or an AP, and the second device may also be a STA or an AP, which is not specifically limited.

[0172] In this patent solution, when the second device is an AP, the first device can also be an AP. That is, the AP of the first device sends the first frame, and the receiving address of the first frame is set to the MAC address of the AP. After sending the first frame, the AP of the second device becomes the TXOP holder. In this case, the first device and the second device are the same device, that is, both are APs.

[0173] Below, the channel access method provided in this application is further described in detail, taking the case where the first device is STA 1, the second device is an AP, and the BSS in which STA 1 and the AP are located also includes STA 2 and STA 3. STA 1, STA 2, and STA 3 join the same site group through negotiation with the AP. In the subsequent description, this site group is referred to as site group 1. The AP allocates one or more service time periods to site group 1. The number of STAs and the number of service time periods shown in Figure 8 are exemplary and do not constitute a specific limitation of the embodiments of this application.

[0174] Figure 8 exemplifies the implementation process of a channel access method provided by the present application. As shown in Figure 8, STA 1, STA 2, and STA 3 start competing for the channel after service period 1 arrives. Taking STA 1 as an example, STA 1 starts backing off after detecting that the channel is busy and waiting for the channel to be idle for a DIFS period. When the randomly selected backoff counter value is zero, it sends the first frame to the AP. As shown in Figure 8, the backoff counters of STA 1 and STA 2 back off to zero at the same time at time t1. Then, STA 1 and STA 2 send the first frame to the AP at the same time at time t1. After receiving any first frame, STA 3 updates its own NAV information based on the NAV information carried in the transmission duration field in the first frame, indicating that the channel is busy during this period, and the backoff counter value is frozen (the shaded part in the backoff time of STA 3 in Figure 8 represents the time when the backoff counter is frozen), and no further backoff is continued.

[0175] If the first frame is a frame that does not require a response, the AP becomes the TXOP holder after receiving the first frame and sends a data frame to STA 1 after waiting for a SIFS. After STA 1 correctly receives the data frame and waits for a SIFS, it sends an acknowledgment frame to the AP.

[0176] If the first frame requires a response, the AP sends a response frame after receiving the first frame and waiting for a SIFS duration, and then waits for a SIFS duration to send a data frame to STA 1. After STA 1 correctly receives the data frame and waits for a SIFS duration, it sends an acknowledgment frame to the AP.

[0177] In one possible implementation, the response frame sent by the AP after receiving the first frame may have a frame structure as shown in FIG5 , and the receiving address field of the response frame may be a set value. Optionally, the receiving address field of the response frame may be the same as the sending address field of the first frame received by the AP, but this application is not limited to this.

[0178] Optionally, the STA to which the AP sends data frames can be any STA, not limited to the STAs in site group 1, and the AP can send data frames to one or more STAs at the same time, which is not limited in this application.

[0179] Optionally, the duration that the AP waits before sending a data frame may also be a PIFS duration. The AP may detect an idle channel within the PIFS duration to obtain a bandwidth for the TXOP.

[0180] Optionally, site group 1 may include all members in a BSS, that is, a BSS may be regarded as a site group. Site group 1 may also be a site group including an AP and some STAs in the BSS. A BSS may also include multiple site groups. This application does not specifically limit the size of the site group.

[0181] In one possible implementation, the AP also participates in channel contention, that is, the AP also performs a backoff process in service period 1 and sends the first frame when the backoff counter value is zero. The AP becomes a TXOP holder after sending the first frame. After sending the first frame, the AP waits for a SIFS period before sending a response frame to the first frame, or directly sends a data frame.

[0182] Figure 9 illustrates an exemplary implementation of another channel access method provided by this application. In Figure 9, STA 4, STA 5, STA 6, and STA 7 belong to Site Group 2. The target site for Site Group 2 during Service Period 2 is STA 4, and the target site during Service Period 3 is STA 6. It should be understood that after successfully competing for a channel, all STAs in the site group transfer channel scheduling rights to the target site.

[0183] As shown in Figure 9, STA 5, STA 6, and STA 7 begin to compete for the channel after service period 2 arrives. Taking STA 5 as an example, STA 5 starts backing off after detecting that the channel is busy and waiting for the channel to be idle for a DIFS period. When the randomly selected backoff counter value is zero, it sends the first frame to the AP. As shown in Figure 9, the backoff counters of STA 5 and STA 6 back off to zero at the same time at time t2. Then, STA 5 and STA 6 simultaneously send the first frame to STA 4 at time t1. After receiving any first frame, STA 7 updates its own NAV information based on the NAV information carried in the transmission duration field of the first frame, indicating that the channel is busy during this period. The backoff counter value is frozen (the shaded portion in STA 7's backoff time 1 in Figure 9 represents the time when the backoff counter is frozen), and the backoff does not continue.

[0184] If the first frame is a frame that does not require a response, STA 4 becomes the TXOP holder after receiving the first frame, and sends a data frame to STA 1 after waiting for a SIFS. After STA 5 correctly receives the data frame and waits for a SIFS, it sends an acknowledgment frame to the AP.

[0185] If the first frame is a frame that requires a response, STA 4 sends a response frame after receiving the first frame and waiting for a SIFS period, and then waits for a SIFS period to send a data frame to STA 5. After STA 5 correctly receives the data frame and waits for a SIFS period, it sends a confirmation frame to the AP.

[0186] As shown in Figure 9, STA 4, STA 5, and STA 7 begin to compete for the channel after service period 3 arrives. Taking STA 5 as an example, STA 5 starts backing off after detecting that the channel is busy and waiting for the channel to be idle for a DIFS period. When the randomly selected backoff counter value is zero, STA 5 sends the first frame to the AP. The backoff counters of STA 5 and STA 7 back off to zero at the same time at time t3. Then, STA 5 and STA 7 simultaneously send the first frame to STA 6 at time t1. After receiving any first frame, STA 4 updates its own NAV information based on the NAV information carried in the transmission duration field of the first frame, indicating that the channel is busy during this period. The backoff counter value is frozen (the shaded portion in the backoff time of STA 4 in Figure 9 represents the time when the backoff counter is frozen), and no further backoff occurs.

[0187] If the first frame is a frame that does not require a response, STA 6 becomes the TXOP holder after receiving the first frame, and sends a data frame to STA 1 after waiting for a SIFS. After STA 5 correctly receives the data frame and waits for a SIFS, it sends an acknowledgment frame to the AP.

[0188] If the first frame is a frame that requires a response, STA 6 sends a response frame after receiving the first frame and waiting for a SIFS period, and then waits for a SIFS period to send a data frame to STA 5. After STA 5 correctly receives the data frame and waits for a SIFS period, it sends a confirmation frame to the AP.

[0189] The second device described in the above embodiment can be STA 4 corresponding to service period 2 in Figure 9 or STA 6 corresponding to service period 3, and the first device can be STA 5 corresponding to service period 2 in Figure 9 or STA 5 corresponding to service period 3, but this application is not limited to this.

[0190] A site group consisting of multiple STAs can be established in the following ways:

[0191] Method 1: Multiple STAs join the same site group through negotiation with the AP. The AP is responsible for allocating service periods for the site group and specifying target sites for each service period. Optionally, the negotiation process between multiple STAs and the AP can refer to the B-TWT mechanism or R-TWT mechanism shown in Figure 7, or the AP can directly specify the group to which each STA belongs through configuration information. This application does not specifically limit this process.

[0192] Method 2: One of the multiple STAs acts as a leader (header). Other STAs join the site group established by the header STA through negotiation with the header STA. The header STA allocates service time periods for the site group and specifies target sites for each service time period.

[0193] Optionally, the negotiation process between other STAs and the header STA may be a process in which other STAs apply to the header STA to join, or a process in which the header STA directly configures each STA, which is not limited in this application.

[0194] In a possible implementation, the header STA may be the target station for some or all service periods in the station group.

[0195] Method 3: Multiple stations negotiate to establish a site group. For example, STA 1 and STA 2 first negotiate to establish site group 3. If STA 3 wishes to join site group 3, it must obtain consent from both STA 1 and STA 2. After STA 3 joins site group 3, if STA 4 wishes to join the same site group, it must obtain consent from STA 1, STA 2, and STA 3, respectively. This process is analogous to the previous one. This application does not limit the number of STAs in a site group.

[0196] In a possible implementation, a target site of a site group formed by two-by-two negotiation among multiple sites may also be generated through two-by-two negotiation. The generation of the target site requires the consent of all STAs in the site group.

[0197] In one possible implementation, the service period of a site group formed by negotiation between multiple sites can be specified by the target site or determined by negotiation between members of the site group. It should be understood that the service periods corresponding to the target sites should not overlap.

[0198] Optionally, the method provided in the embodiment of the present application may be applicable to a peer-to-peer (P2P) site or a mesh (MESH) site, but the present application does not limit this.

[0199] The above, in conjunction with Figures 1 to 9, describes in detail the channel access method of an embodiment of the present application. The following, in conjunction with Figures 10 and 11, describes in detail the device for implementing the channel access method. The channel access device includes a module or unit for executing each part corresponding to the above embodiment. Each module or unit can be software, hardware, or a combination of software and hardware. The following only briefly illustrates the channel access device. For the details of the implementation of the solution, please refer to the description of the aforementioned method embodiment, which will not be repeated below.

[0200] FIG10 is a schematic block diagram of a channel access device 1000 provided in an embodiment of the present application. As shown in FIG10 , the device 1000 includes: a processing module 1001 and a transceiver module 1002 .

[0201] In a possible implementation, the channel access apparatus 1000 is configured to execute the steps and processes corresponding to the first device in the above method 300 .

[0202] Among them, the processing module 1001 is used to: execute the backoff process; the transceiver module 1002 is used to: when the value of the backoff counter is zero, send a first frame to the second device, the protocol data unit PPDU format of the first frame is a set format, and the frame control field, transmission duration field, address field and scrambling code seed included in the first frame are all set values, and the first frame is used to transfer the channel scheduling right to the second device.

[0203] Optionally, the address field includes a receiving address field and a sending address field, the receiving address field is the MAC address of the second device, and the sending address field is a set MAC address.

[0204] Optionally, at least one of the following fields in the frame control field is set to 1: To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field, and Protected Frame field.

[0205] Optionally, the first device belongs to the first group, the PPDU format of the first frame sent by different devices in the first group is the same, and the following fields included in the first frame sent by different devices in the first group have the same values: frame control field, transmission duration field, address field and scrambling code seed.

[0206] Optionally, the transceiver module 1002 is further used to: receive first configuration information from the second device, where the first configuration information is used to indicate that the first device belongs to the first group.

[0207] Optionally, the transceiver module 1002 is also used to: receive group indication information from the second device, the group indication information including the group identifier of at least one group; based on the group indication information, send a first request to the second device, the first request being used to request to join a first group in at least one group; and receive a first response from the second device to the first request.

[0208] Optionally, the first group is grouped through a broadcast target wake-up time B-TWT mechanism or a restricted target wake-up time R-TWT mechanism.

[0209] Optionally, the transceiver module 1002 is further configured to: receive second configuration information, where the second configuration information is used to configure the first service period; and the processing module 1001 is specifically configured to: execute the backoff process within the first service period.

[0210] Optionally, the first device is an access point AP or a non-access point non-AP STA.

[0211] Optionally, the first frame is a request to send RTS frame or a clear to send CTS frame.

[0212] Optionally, the PPDU format is a non-HT PPDU or a non-HT duplicate PPDU.

[0213] In another possible implementation, the channel access apparatus 1000 is configured to execute the steps and processes corresponding to the second device in the above method 300 .

[0214] Among them, the transceiver module 1002 is used to: receive the first frame, the protocol data unit PPDU format of the first frame is the set format, the frame control field, transmission duration field, address field and scrambling code seed included in the first frame are all set values, and the first frame is used to transfer the channel scheduling right to the second device; and, send data or trigger frame, the trigger frame is used to schedule uplink data.

[0215] Optionally, the transceiver module 1002 is further used to: receive a second frame sent by a third device, the PPDU format, frame control field, transmission duration field, address field and scrambling code seed of the second frame are the same as those of the first frame.

[0216] Optionally, the first frame is a frame requiring a response, the address field includes a receiving address field and a sending address field, the receiving address field is a media access control MAC address of the second device, and the sending address field is a set MAC address.

[0217] Optionally, at least one of the following fields in the frame control field is set to 1: To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field, and Protected Frame field.

[0218] Optionally, the transceiver module 1002 is further used to: send first configuration information to the first device, where the first configuration information is used to indicate that the first device belongs to the first group.

[0219] Optionally, the transceiver module 1002 is also used to: send group indication information, the group indication information includes a group identifier of at least one group; receive a first request from a first device, the first request is used to request to join a first group in at least one group; and send a first response to the first request to the first device.

[0220] Optionally, the first group is grouped through a broadcast target wake-up time B-TWT mechanism or a restricted target wake-up time R-TWT mechanism.

[0221] Optionally, the first device belongs to the first group, the PPDU format of the first frame sent by different devices in the first group is the same, and the following fields included in the first frame sent by different devices in the first group have the same values: frame control field, transmission duration field, address field and scrambling code seed.

[0222] Optionally, the transceiver module 1002 is further configured to: send second configuration information to the first device, where the second configuration information is used to configure a first service period; and the first device performs a backoff process within the first service period.

[0223] Optionally, the second device is an access point AP or a non-access point station non-AP STA.

[0224] Optionally, the first frame is a request to send RTS frame or a clear to send CTS frame.

[0225] Optionally, the PPDU format is a non-HT PPDU or a non-HT duplicate PPDU.

[0226] It should be understood that the device 1000 here is embodied in the form of a functional module. The term "module" here can refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (such as a shared processor, a proprietary processor or a group processor, etc.) and a memory for executing one or more software or firmware programs, a combined logic circuit and / or other suitable components that support the described functions. In an optional example, those skilled in the art will understand that the device 1000 can be specifically the first device or the second device in the above-mentioned embodiment, and the device 1000 can be used to execute the various processes and / or steps corresponding to the first device or the second device in the above-mentioned method embodiment. To avoid repetition, they will not be described here.

[0227] The above-mentioned device 1000 has the function of implementing the corresponding steps performed by the first device or the second device in the above-mentioned method; the above-mentioned functions can be implemented by hardware, or by hardware executing corresponding software implementation. The hardware or software includes one or more modules corresponding to the above-mentioned functions. For example, the above-mentioned transceiver module 1002 may include a sending module and a receiving module. The sending module can be used to implement the various steps and / or processes for performing the sending action corresponding to the above-mentioned transceiver module, and the receiving module can be used to implement the various steps and / or processes for performing the receiving action corresponding to the above-mentioned transceiver module. The sending module can be replaced by a transmitter, and the receiving module can be replaced by a receiver, respectively performing the sending and receiving operations and related processing operations in each method embodiment.

[0228] In an embodiment of the present application, the device 1000 in FIG. 10 may also be a chip, such as a SOC.

[0229] Figure 11 shows a schematic block diagram of a channel access device 1100 provided in an embodiment of the present application. The device 1100 includes a processor 1101, a transceiver 1102, and a memory 1103. The processor 1101, the transceiver 1102, and the memory 1103 communicate with each other via an internal connection path. The memory 1103 is used to store instructions, and the processor 1101 is used to execute the instructions stored in the memory 1103 to control the transceiver 1102 to send and / or receive signals.

[0230] It should be understood that apparatus 1100 may be specifically the first device or the second device in the above-described embodiment, and may be used to execute the various steps and / or processes corresponding to the first device or the second device in the above-described method embodiment. Optionally, the memory 1103 may include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. For example, the memory may also store device type information. The processor 1101 may be used to execute instructions stored in the memory, and when the processor 1101 executes the instructions stored in the memory, the processor 1101 is used to execute the various steps and / or processes of the above-described method embodiment. The transceiver 1102 may include a transmitter and a receiver. The transmitter may be used to implement the various steps and / or processes corresponding to the above-described transceiver for performing a sending action, and the receiver may be used to implement the various steps and / or processes corresponding to the above-described transceiver for performing a receiving action.

[0231] It should be understood that in the embodiments of the present application, the processor may be a central processing unit (CPU), or may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0232] During implementation, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or by instructions in the form of software. The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware processor, or can be executed by a combination of hardware and software modules in the processor. The software module can be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor executes the instructions in the memory, and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it will not be described in detail here.

[0233] The present application also provides a computer-readable storage medium, which is used to store a computer program, and the computer program is used to implement the method shown in the above method embodiment.

[0234] The present application also provides a computer program product, which includes a computer program (also referred to as code or instructions). When the computer program runs on a computer, the computer can execute the method shown in the above method embodiment.

[0235] Those skilled in the art will appreciate that the modules and algorithm steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel 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.

[0236] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and modules described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0237] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0238] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules may be selected to achieve the purpose of the present embodiment according to actual needs.

[0239] In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0240] If the functions are implemented in the form of software function modules 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 the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0241] The above description is merely a specific embodiment of the present application, but the scope of protection of the embodiments of the present application is not limited thereto. Any person skilled in the art can easily conceive of changes or substitutions within the technical scope disclosed in the embodiments of the present application, and such changes or substitutions should be included in the scope of protection of the embodiments of the present application. Therefore, the scope of protection of the embodiments of the present application should be based on the scope of protection of the claims.

Claims

1. A channel access method, characterized in that: include: The first device performs a backoff procedure; When the value of the backoff counter is zero, a first frame is sent to the second device, the protocol data unit PPDU format of the first frame is a set format, the frame control field, transmission duration field, address field and scrambling code seed included in the first frame are all set values, and the first frame is used to transfer the channel scheduling right to the second device.

2. The method according to claim 1, characterized in that The address field includes a receiving address field and a sending address field, the receiving address field is the MAC address of the second device, and the sending address field is a set MAC address.

3. The method according to claim 1 or 2, characterized in that: At least one of the following fields in the frame control field is set to 1: To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field, and Protected Frame field.

4. The method according to any one of claims 1 to 3, characterized in that The first device belongs to the first group, the PPDU format of the first frame sent by different devices in the first group is the same, and the following fields included in the first frame sent by different devices in the first group have the same values: frame control field, transmission duration field, address field and scrambling code seed.

5. The method according to claim 4, characterized in that The method further comprises: The first device receives first configuration information from the second device, where the first configuration information is used to indicate that the first device belongs to the first group.

6. The method according to claim 4, characterized in that The method further comprises: The first device receives grouping indication information from the second device, where the grouping indication information includes a group identifier of at least one group; The first device sends a first request to the second device based on the grouping indication information, where the first request is used to request to join a first group in the at least one group; The first device receives a first response to the first request from the second device.

7. The method according to claim 6, characterized in that The first group is grouped by a broadcast target wake-up time B-TWT mechanism or a restricted target wake-up time R-TWT mechanism.

8. The method according to any one of claims 1 to 6, characterized in that The method further comprises: The first device receives second configuration information, where the second configuration information is used to configure a first service period; The first device performs a backoff process, including: The first device performs a backoff procedure during the first service period.

9. The method according to any one of claims 1 to 8, characterized in that The first device is an access point AP or a non-access point station non-AP STA.

10. The method according to any one of claims 1 to 9, characterized in that The first frame is a request to send RTS frame or a clear to send CTS frame.

11. The method according to any one of claims 1 to 10, characterized in that The PPDU format is a non-HT PPDU or a non-HT duplicate PPDU.

12. A channel access method, characterized in that: include: The second device receives a first frame, wherein a protocol data unit PPDU format of the first frame is a set format, a frame control field, a transmission duration field, an address field, and a scrambling code seed included in the first frame are all set values, and the first frame is used to transfer the channel scheduling right to the second device; The second device sends data or a trigger frame, where the trigger frame is used to schedule uplink data.

13. The method according to claim 12, characterized in that The method also includes: The second device receives a second frame sent by the third device, and the PPDU format, frame control field, transmission duration field, address field and scrambling code seed of the second frame are the same as those of the first frame.

14. The method according to claim 12 or 13, characterized in that The address field includes a receiving address field and a sending address field, the receiving address field is a media access control MAC address of the second device, and the sending address field is a set MAC address.

15. The method according to any one of claims 12 to 14, characterized in that At least one of the following fields in the frame control field is set to 1: To DS field, From DS field, More Fragments field, Retry field, Power Management field, More Data field, and Protected Frame field.

16. The method according to any one of claims 12 to 15, characterized in that The method further comprises: The second device sends first configuration information to the first device, where the first configuration information is used to indicate that the first device belongs to a first group.

17. The method according to any one of claims 12 to 15, characterized in that The method further comprises: The second device sends grouping indication information, where the grouping indication information includes a group identifier of at least one group; The second device receives a first request from the first device, where the first request is used to request to join a first group of the at least one group; The second device sends a first response to the first request to the first device.

18. The method according to claim 17, characterized in that The first group is grouped by a broadcast target wake-up time B-TWT mechanism or a restricted target wake-up time R-TWT mechanism.

19. The method according to any one of claims 12 to 17, characterized in that The first device belongs to the first group, the PPDU format of the first frame sent by different devices in the first group is the same, and the following fields included in the first frame sent by different devices in the first group have the same values: frame control field, transmission duration field, address field and scrambling code seed.

20. The method according to any one of claims 12 to 17, characterized in that The method further comprises: The second device sends second configuration information to the first device, where the second configuration information is used to configure the first service period; The first device performs a backoff procedure during the first service period.

21. The method according to any one of claims 12 to 20, characterized in that The second device is an access point AP or a non-access point station non-AP STA.

22. The method according to any one of claims 12 to 21, characterized in that The first frame is a request to send RTS frame or a clear to send CTS frame.

23. The method according to any one of claims 12 to 22, characterized in that The PPDU format is a non-HT PPDU or a non-HT duplicate PPDU.

24. A channel access device, characterized in that: A module comprising the method of any one of claims 1 to 11, or a module comprising the method of any one of claims 12 to 23.

25. A channel access device, characterized in that: include: A processor, wherein the processor is coupled to a memory, wherein the memory is used to store a computer program, and when the processor calls the computer program, the device executes the method as claimed in any one of claims 1 to 11, or the method as claimed in any one of claims 12 to 23.

26. A computer-readable storage medium, characterized in that: Used to store a computer program, the computer program comprising instructions for implementing the method according to any one of claims 1 to 11, or instructions for implementing the method according to any one of claims 12 to 23.

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