Data transmission method and device

Abstract

[0003] To reduce the possibility of collisions during transmission and communication latency, a data transmission method and apparatus are provided, which relate to the field of wireless communication technology. In the method, a first device may transmit a first frame without performing channel listening. The first device may access a channel by using the first frame. If data is not being transmitted on the channel, the first device may preempt the channel by using the first frame. If data is being transmitted on the channel, the first frame may interrupt data transmission. Furthermore, if the first device detects that the channel state is idle, it waits for a first duration before transmitting a second frame, thereby avoiding collisions of the second frame. The method and apparatus may be applied to wireless local area network systems supporting 802.11 series protocols, for example, next-generation Wi-Fi protocols such as IEEE 802.11ax, such as 802.11be, Wi-Fi 7, or EHT, or next-generation Wi-Fi protocols such as Wi-Fi 8.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to Chinese Patent Application No. 202211132100.0, entitled "DATA TRANSMISSION METHOD AND APPARATUS," filed with the State Intellectual Property Office of the People's Republic of China on September 16, 2022, which is incorporated herein by reference in its entirety.

[0002] The present application relates to the field of wireless communication technology, and in particular to a data transmission method and apparatus. [Background technology]

[0003] Currently, in Wi-Fi® communication systems, nodes need to transmit data based on the carrier sense multiple access (CSMA) protocol. CSMA introduces a listen-before-talk (LBT) mechanism. The concept of CSMA in the LBT mechanism is that "before each data transmission, a node first listens to whether the channel is idle. If the channel is not idle, the node will not transmit data. A node can transmit data only when the channel is idle to avoid interrupting the ongoing transmission process of another device." In CSMA, a node also needs to perform a random backoff process before each data transmission. However, in a channel access scheme based on CSMA random backoff, there is a probability of collision, and after each collision, the backoff window increases exponentially. Furthermore, the presence of more simultaneous users leads to a higher collision probability and longer access latency. Although Wi-Fi communication has good performance in terms of average latency, there exists a possibility of collision during access, which results in a long tail latency of Wi-Fi communication. Summary of the Invention

[0004] The embodiments of the present application provide a data transmission method and apparatus to reduce the probability of collision during a single transmission and reduce communication latency.

[0005] According to a first aspect, there is provided a data transmission method. The method may be performed by a first device or a chip / chip system. In the method, the first device transmits a first frame to a second device. When transmitting the first frame, the first device does not need to perform channel listening. If the first device detects that the channel state is idle, the first device waits for a first duration and then transmits a second frame.

[0006] According to this solution, a first device may transmit a first frame without performing channel listening. The first device may access a channel by using the first frame. If no data is being transmitted on the channel, the first device may preempt the channel by using the first frame. If data is being transmitted on the channel, the first frame may interrupt the data transmission. Furthermore, if the first device detects that the channel state is idle, it may transmit a second frame after waiting for a first duration, thereby reducing or avoiding frame loss caused by collision of the second frame.

[0007] In one possible embodiment, the first duration is less than or equal to (point interframe space, PIFS). It can be understood that PIFS may be the PIFS in the prior art, for example, 25 microseconds, or may be an extension of the prior art. Based on the above solution, the first duration is less than or equal to PIFS, so that the waiting duration of the second device can be reduced, and the latency of the second frame can be reduced.

[0008] In one possible embodiment, the first frame includes a first duration field, the first duration field indicates a second duration, and the second frame is transmitted within the second duration. For example, the start time of the second duration is within the first frame. At the start time of and an end time of the second duration may be a start time of the second frame. Optionally, the receiving address in the first frame is an address of the second device.

[0009] In the related art, the duration field indicates the duration for occupying the channel. Therefore, after receiving and parsing the duration field in the frame, another device does not transmit data within the duration indicated by the duration field. Therefore, based on the above solution, the duration field is set to a second duration, thereby achieving the purpose of occupying the channel for the second duration. During the second duration, another device does not access the channel to transmit data. Therefore, the reliability of the second frame may be improved and the possibility of frame loss caused by collision of the second frame may be reduced.

[0010] In one possible embodiment, a first device receives a third frame from a third device. The first device does not transmit an acknowledgement frame for the third frame. For example, the first device may receive the third frame from the third device before transmitting the first frame. If the first device does not transmit an acknowledgement frame for the third frame, the transmitting end of the third frame considers the third frame lost and waits for the acknowledgement frame to time out before re-accessing the channel. Thus, an opportunity to transmit a second frame may be provided. In one possible scenario, the above solution may interrupt a burst sequence of a greedy terminal.

[0011] In one possible embodiment, the first frame may not need to be replied with an acknowledgement frame. For example, the acknowledgement frame indicator field indicates that the first frame does not need to be replied with an acknowledgement frame. Based on the above solution, the first device may quickly preempt the channel by using a first frame that does not need to be replied with an acknowledgement frame. Furthermore, because the first frame does not need to be replied with an acknowledgement frame, a collision of the first frame with a frame being transmitted on the channel does not affect the first device.

[0012] In one possible embodiment, the first frame comprises a control frame, for example a clear to send (CTS) frame, or the first frame comprises a data frame.

[0013] In one possible embodiment, the receiving address in the first frame is the address of the first device. Based on this solution, because the receiving address in the first frame is the address of the first device, another device will not reply with an acknowledgement frame after receiving the first frame, and therefore the first frame will not be replied with an acknowledgement frame.

[0014] In one possible embodiment, after the first device transmits a second frame, the first device receives an acknowledgment frame transmitted by the second device for the second frame. The first device receives a fourth frame transmitted by the second device. The second frame includes a second duration field, the second duration field indicates a third duration, and the fourth frame is transmitted within the third duration.

[0015] In the related art, the duration field indicates the duration for occupying the channel. Therefore, after receiving and parsing the duration field in the frame, another device does not transmit data within the duration indicated by the duration field. Therefore, based on the above solution, the duration field is set to a third duration, and during the third duration, devices other than the first device and / or the receiving end of the second frame, i.e., the second device, cannot access the channel to transmit data, so that the channel is reserved.

[0016] According to a second aspect, a communication device is provided comprising a processing unit and a transceiver unit. A device (e.g., a first device) Provided.

[0017] The transceiver unit is configured to transmit a first frame to a second device. The first device does not need to perform channel listening when transmitting the first frame. The processing unit is configured to detect a channel condition. The transceiver unit is further configured to transmit a second frame after waiting a first duration if the channel condition is detected to be idle.

[0018] In one possible embodiment, the first duration is less than or equal to a PIFS, which may be understood to be a PIFS in the prior art, for example, 25 microseconds, or may be an extension of the prior art.

[0019] In one possible embodiment, the first frame includes a first duration field, the first duration field indicates a second duration, and the second frame is transmitted within the second duration. For example, the start time of the second duration is , at the start time of the first frame and the end time of the second duration may be the start time of the second frame.

[0020] Optionally, the receiving address in the first frame is an address of the second device.

[0021] In one possible embodiment, the transceiver unit is further configured to receive a third frame from a third device, and the processing unit is further configured to determine not to transmit an acknowledgement frame for the third frame.

[0022] In one possible implementation, the first frame may not need to be returned in an acknowledgement frame, for example, the acknowledgement frame indicator field may indicate that the first frame does not need to be returned in an acknowledgement frame.

[0023] In one possible embodiment, the first frame comprises a control frame, for example a clear to send (CTS) frame, or the first frame comprises a data frame.

[0024] In one possible embodiment, the receiving address in the first frame is the address of the first device.

[0025] In one possible embodiment, the transceiver unit is further configured to receive an acknowledgment frame transmitted by the second device for the second frame. The transceiver unit is further configured to receive a fourth frame transmitted by the second device. The second frame includes a second duration field, the second duration field indicating a third duration, and the fourth frame is transmitted within the third duration.

[0026] According to a third aspect, there is provided a communication device. The communication device may be the communication device in any possible implementation of the second aspect of the above-mentioned embodiments, or may be a chip disposed in the communication device in any one of the second aspects. The communication device comprises a communication interface and a processor, and optionally further comprises a memory. The memory is configured to store a computer program, an instruction, or data. The processor is coupled to the memory and the communication interface. When the processor reads the computer program, the instruction, or the data, the communication device is capable of executing the method executed by the first device in any possible implementation of the first aspect.

[0027] It should be understood that the communication interface may be implemented by using an antenna, a feeder, a codec, etc. in the communication device. Alternatively, if the communication device is a chip located in a network device or a terminal device, the communication interface may be an input / output interface of the chip, e.g., input / output pins. The communication device may further comprise a transceiver used by the communication device to communicate with another device.

[0028] According to a fourth aspect, an embodiment of the present application provides a chip system. The chip system includes a processor and may further include a memory, and is configured to implement the method performed by the communication device in any possible implementation of the first aspect. In one possible implementation, the chip system further includes a memory configured to store program instructions and / or data. The chip system may include a chip, or may include a chip and another discrete device.

[0029] According to a fifth aspect, the present application provides a computer-readable storage medium storing a computer program or instructions that, when executed, perform the method performed by the first device in the aforementioned aspect.

[0030] According to a sixth aspect, there is provided a computer program product comprising computer program code or instructions that, when executed, perform the method performed by the first device in the previous aspect.

[0031] According to a seventh aspect, there is provided a communication device, comprising a unit or module configured to perform the method of the previous aspect.

[0032] According to an eighth aspect, there is provided a chip system comprising a logic circuit and an input / output unit, the logic circuit configured to perform the method performed by the first device in any possible implementation of the first aspect, the input / output unit being used by the first device to communicate with another apparatus, for example a second device.

[0033] For the beneficial effects of the second to eighth aspects and the implementations of the second to eighth aspects, please refer to the description of the beneficial effects of the method in the first aspect and the implementations of the first aspect. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a diagram of a network architecture according to an embodiment of the present application. [Figure 2A] FIG. 10 is a diagram of latency based on random backoff. [Figure 2B] 1 is a diagram of the latency tail of a Wi-Fi system. [Figure 3] FIG. 1 is a scenario diagram of a data transmission method based on time slices. [Figure 4A] 1 is a diagram showing various types of service packets in EDCA. [Figure 4B] FIG. 1 illustrates a scenario in which a channel is preempted by using a PIFS. [Figure 5] FIG. 1 is a diagram of a data collision. [Figure 6A] FIG. 1 is a diagram of the transmission characteristics of a greedy terminal. [Figure 6B] 1 is a diagram of collisions between burst and service packets of a greedy terminal; [Figure 7] 1 is an exemplary flowchart of a data transmission method according to an embodiment of the present application; [Figure 8] FIG. 2 is a diagram of a possible first frame structure according to an embodiment of the present application. [Figure 9] FIG. 10 is a diagram of another possible first frame structure according to an embodiment of the present application. [Figure 10A] FIG. 2 is a scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 10B] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 11A] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 11B] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 12] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 13] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 14] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 15A] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 15B] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 15C] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 16] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 17] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 18] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 19] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 20] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 21] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 22] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 23] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 24] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 25] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 26] FIG. 2 is another scenario diagram of a data transmission method according to an embodiment of the present application; [Figure 27] 1 is a diagram of a communication device according to an embodiment of the present application; [Figure 28] FIG. 1 is a diagram of another communication device according to an embodiment of the present application. [Figure 29] FIG. 1 is a diagram of another communication device according to an embodiment of the present application. [Figure 30] FIG. 1 is a diagram of another communication device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0035] In the embodiments of the present application, "after" and "before" may be understood as an order relationship of transmission times or an order relationship of reception times. For example, "first information being after a first field" may be understood as "the transmission time of the first information is later than the transmission time of the first field" or "the reception time of the first information is later than the reception time of the first field." As another example, "first information being before a second field" may be understood as "the transmission time of the first information is earlier than the transmission time of the second field" or "the reception time of the first information is earlier than the reception time of the second field."

[0036] Embodiments of the present application may be applicable to WLAN scenarios, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 system standards, such as 802.11a / b / g, 802.11n, 802.11ac, 802.11ax, or the next generation of 802.11ax, such as the 802.11be standard, Wi-Fi 7, or extremely high throughput (EHT), 802.11ad, 802.11ay, 802.11bf, or the next generation of 802.11be, such as Wi-Fi 8 or the next generation standard. Alternatively, embodiments of the present application may be applicable to wireless local area network systems, such as internet of things (IoT) networks or vehicle-to-everything (V2X) networks.

[0037] In the following, an example in which the embodiments of the present application can be applied to a WLAN scenario will be used. It should be understood that WLAN has evolved from the 802.11a / g standard and includes 802.11n, 802.11ac, 802.11ax, and 802.11be, which are currently being discussed. 802.11n may be referred to as high throughput (HT), 802.11ac may be referred to as very high throughput (VHT), 802.11ax may be referred to as high efficiency (HE), or Wi-Fi 6 and 802.11be may be referred to as EHT or Wi-Fi 7, and standards before HT, such as 802.11a / b / g, may be collectively referred to as non-high throughput (Non-HT).

[0038] FIG. 1 is a diagram of a network architecture of a WLAN to which an embodiment of the present application can be applied. In FIG. 1, a WLAN including one wireless access point (AP) and two stations (STAs) is used as an example. The STAs can receive wireless frames transmitted by the AP and can also transmit wireless frames to the AP. Furthermore, the embodiment of the present application can also be applied to communication between APs. For example, APs may communicate with each other by using a distributed system (DS). The embodiment of the present application can also be applied to communication between STAs. It should be understood that the number of APs and STAs in FIG. 1 is merely an example. There may be more or fewer APs and STAs.

[0039] An access point may be an access point through which a terminal device (e.g., a mobile phone) accesses a wired (or wireless) network, and is mainly deployed in homes, buildings, and campuses, with a typical coverage radius ranging from tens of meters to hundreds of meters. Of course, an access point may alternatively be deployed outdoors. An access point is equivalent to a bridge connecting a wired network and a wireless network. The main function of an access point is to connect various wireless network clients together and then connect the wireless network to Ethernet. Specifically, an access point may be a terminal device (e.g., a mobile phone) or a network device (e.g., a router) with a Wi-Fi chip. An access point may be a device supporting the 802.11be standard. Alternatively, the access point may be a device that supports multiple wireless local area network (WLAN) standards in the 802.11 family, such as 802.11ax, 802.11ac, 802.11ad, 802.11ay, 802.11n, 802.11g, 802.11b, 802.11a, and the next generation of 802.11be.

[0040] The station may be a wireless communication chip, a wireless sensor, a wireless communication terminal, etc., and may be referred to as a user. For example, the station may be a mobile phone, a tablet computer, a set-top box, a smart television set, a smart wearable device, an in-vehicle communication device, a computer, etc., that support Wi-Fi communication functions. Optionally, the station may support the 802.11be standard. Alternatively, the station may support multiple wireless local area network (WLAN) standards of the 802.11 family, such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, 802.11a, and the next generation of 802.11be.

[0041] For example, the access points and stations may be devices used in the Internet of Vehicles, Internet of Things nodes or sensors in the Internet of Things (IoT), may be smart cameras, smart remote controls or smart water / electricity meters in a smart home or may be sensors in a smart city.

[0042] The AP and STA in the embodiment of the present application may be APs and STAs applicable to the IEEE 802.11 system standard. The AP is a device deployed in a wireless communication network to provide wireless communication functions for STAs associated with the AP. The AP may be used as a hub of the communication system and is typically a network-side product supporting the MAC and PHY of the 802.11 system standard, and may be a communication device such as a router, gateway, repeater, communication server, switch, or bridge. For ease of explanation, the above-mentioned devices are collectively referred to as APs in this specification. The STA is typically a terminal product supporting the media access control (MAC) and physical layer (PHY) of the 802.11 system standard, such as a mobile phone or a notebook computer.

[0043] It can be understood that the first device in the embodiment of the present application may be an AP or a STA. Similarly, the second device in the embodiment of the present application may be an AP or a STA.

[0044] Currently, in Wi-Fi communication systems, nodes (e.g., APs or STAs) need to transmit data based on the carrier sense multiple access (CSMA) protocol. CSMA introduces a listen-before-talk (LBT) mechanism. The concept of CSMA in the LBT mechanism is that "before each data transmission, a node first listens to whether the channel is idle by using a clear channel assessment (CCA) technique. If the channel is not idle, the node does not transmit data. A node may transmit data only when the channel is idle to avoid interrupting the ongoing transmission process of another device." In CSMA, a node also needs to perform a random backoff process before each data transmission. Specifically, before transmitting data, a node may randomly generate a random backoff count value based on specified parameters. A node may listen to the channel in each slot. If the channel condition is idle, the node may perform random backoff, i.e., the random backoff count value is decremented by 1. If the channel condition is not idle, the random backoff count value is not decremented by 1. The node may transmit data only if the random backoff count value is 0.

[0045] However, as shown in Figure 2A, in a channel access scheme based on CSMA random backoff, there is a probability of collision, and after each collision, the backoff window increases exponentially. Furthermore, the presence of more simultaneous users results in a higher collision probability and longer access latency. As shown in Figure 2B, Wi-Fi communication has good performance in terms of average latency, but there is a possibility of collision during access, resulting in a long tail latency of Wi-Fi communication.

[0046] Currently, low latency and high reliability scenarios have become new opportunities and growth points for WLAN products. Latency requirements are becoming increasingly higher for existing industrial scenarios, home gaming scenarios, etc. In such scenarios, people are concerned about tail latency. However, it is difficult to ensure the success rate of a single transmission in Wi-Fi communication. Specifically, when the link layer is reliable, collisions in a single transmission cannot be avoided, thus requiring retransmission, which causes tail latency. Therefore, methods for reducing tail latency in Wi-Fi communication, i.e., methods for ensuring the reliability of a single transmission, are particularly important.

[0047] In order to improve the reliability of a single transmission and reduce or avoid data collisions, data can currently be transmitted in the following two ways:

[0048] Scheme 1: To avoid collisions and air interface contention, data transmissions of all nodes are managed and ordered by the AP. The AP assigns a time slice to each node, and each node transmits data based on the time slice. See FIG. 3. The AP may assign slots to five nodes. For example, node 1 corresponds to slot 1 (slot 1), node 2 corresponds to slot 2, node 3 corresponds to slot 3, node 4 corresponds to slot 4, and node 5 corresponds to slot 5. In this way, the five nodes may transmit data in turn in each cycle. It may be understood that each slot is allowed to be used only by the corresponding node. For example, slot 1 is allowed to be used only by node 1, and only node 1 may transmit or receive data in slot 1.

[0049] However, the above-mentioned method 1 is not applicable to the lowest latency scenarios. For example, in a home network, neighbors cannot be required to use devices provided by the same vendor. Therefore, it is relatively difficult to implement because all devices must be provided by the same vendor.

[0050] Method 2:

[0051] See Figure 4A. The concept of enhanced distributed channel access (EDCA) is introduced in 802.11e. Based on EDCA, packets from higher layers are classified into four types of service packets: background (BK), best effort (BE), video (VI), and voice (VO). For each service packet, a set of EDCA parameters is defined, as shown in Table 1.

[0052] Table 1: Example EDCA parameters [Table 1] The EDCA parameters determine the probability of occupying the channel by each type of service packet, and can ensure that high-priority service packets have a greater opportunity to occupy the channel than low-priority service packets. The channel contention priorities of various service packets may be adjusted by adjusting and controlling the EDCA parameters of each service packet to adjust the latency and throughput performance of different services.

[0053] In a typical case, the AIFSN is greater than or equal to 2. That is, random backoff can be initiated only after waiting in a queue of AIFSN at least equal to the distributed interframe space (DIFS). DIFS = 2 × duration of one slot (9 microseconds) + duration of one short frame space (16 microseconds). When a background service packet arrives at a background STA, the service packet is being transmitted on the air interface, i.e., the current channel state is busy. In this case, random backoff can be initiated only after the current service packet ends and the duration of channel idle for the background STA's transmission reaches at least DIFS = 34 microseconds (μs). After random backoff is completed, the background STA may transmit the background service packet.

[0054] A normal frame sequence interval is a short interframe space (SIFS). Therefore, AIFSN is typically not set to 0. If AIFSN is set to 0, service packets will always collide with frame sequences. Therefore, an extreme configuration for EDCA is to set AIFSN to 1 and have the node not perform random backoff. That is, the node transmits a service packet when it determines that the duration the channel has been idle has reached a point interframe space (PIFS). The purpose of preemption using PIFS is to preempt the channel more quickly than other nodes, thereby reducing the impact of access latency.

[0055] Please refer to FIG. 4B. When a low-latency service reaches the AP, the AP performs channel listening. Since the background STA is transmitting background service packets, the channel state is "busy". The AP continues to perform channel listening. After determining that the duration for which the channel is idle has reached PIFS, the AP may transmit a service packet for the low-latency service. It can be understood that when the background STA retransmits a background service packet, the background STA needs to perform a random backoff after waiting only DIFS for which the channel is idle. The background service packet can be transmitted only after the random backoff has ended. However, since PIFS < DIFS, that is, the waiting duration of the AP is less than the waiting duration of the background STA, the AP can first preempt the channel and transmit the data packet of the low-latency service without collision.

[0056] Although the PIFS waiting time is short and the AP may have priority access to the channel, the following two possible collisions may still occur: (1) When a low-latency service arrives, the AP performs channel listening and determines that the channel state is idle. At the same time, another node is performing random backoff, and the remaining backoff duration is exactly three slots close to PIFS. In this case, packet loss may occur due to collision. See FIG. 5. At time t2, a low-latency service arrives at the AP, and the AP may determine through channel listening that the channel is idle. Therefore, after determining that the channel idle duration has reached PIFS, the AP may transmit a data packet of the low-latency service at time t3. However, because a background service packet arrives at the background STA at time t1, the background STA may perform random backoff after the channel idle duration has reached DIFS. At time t2, the remaining backoff duration is three slots close to PIFS. At time t3, the random backoff ends, and the background STA transmits the background service packet. It can be seen from Figure 5 that data packets of low latency services collide with background service packets. Therefore, data packets of low latency services and background service packets may be lost. (2) Some terminals do not comply with the transmission opportunity (TXOP) limit constraint. These terminals continuously occupy the air interface when transmitting service packets. Therefore, these terminals are called greedy terminals. See Figure 6A. Greedy terminals are characterized by continuous bursts, each burst typically lasting 10 ms or even longer. Service packets within a burst are transmitted at intervals of SIFS. The interval between bursts may be PIFS.

[0057] When the AP transmits a service packet of a high-priority service having an extreme configuration, for example, a low-latency service, the service packet has a very high tendency to collide with the burst of greedy terminals. Refer to FIG. 6B. The interval between service packets within a burst is SIFS, and SIFS < PIFS. Therefore, the service packet of the low-latency service cannot preempt the channel. After the burst of greedy terminals ends, the greedy terminal transmits the next burst at an interval of PIFS. At this point, the AP also performs preemption by using PIFS, and a collision occurs.

[0058] Therefore, it can be understood that even when PIFS having an extreme configuration is used to preempt the channel, the problems of collision and long-term occupation of the channel cannot be avoided.

[0059] From this perspective, embodiments of the present application provide a data transmission method. In this method, the first device may transmit a first frame without performing channel listening. When detecting that the channel state is idle, the first device may transmit a second frame after waiting for a first duration. In this solution, the first frame may be used to detect or preempt the channel. When data is being transmitted on the channel, the first frame may interrupt the data transmission to protect the second frame of the low-latency service, and thus, frame loss caused by the collision of the second frame is reduced or avoided.

[0060] FIG. 7 is an exemplary flowchart of a data transmission method according to an embodiment of the present application. The following operations may be included.

[0061] S701: The first device transmits a first frame to the second device.

[0062] As described above, the first device does not need to perform channel listening when transmitting the first frame. In other words, the first device may transmit the first frame without determining whether the channel is idle. Optionally, the first device may perform channel listening when transmitting the first frame. For example, the first device may detect whether the channel state is idle through CCA. The first device may transmit the first frame when the channel state is idle. For example, the first device may transmit the first frame when the duration of channel idle reaches a specified duration. The specified duration may be set to less than PIFS, e.g., less than or equal to 25 microseconds, or the specified duration may be SIFS, e.g., 16 microseconds.

[0063] It may be appreciated that the first device may not transmit the first frame if the channel conditions are not idle.

[0064] In one possible embodiment, the first frame may not need to be replied with an acknowledgement frame. For example, the first frame may be a control frame, such as a clear to send (CTS) frame. FIG. 8 is a diagram of a possible first frame structure according to one embodiment of the present application. As shown in FIG. 8, the first frame may be a CTS frame. The first frame may include a frame control field, a duration field, a received address (RA) field, and a frame check sequence (FCS) field. If the first frame is a control frame, the first frame may not need to be replied with an acknowledgement frame. Therefore, the first device may preempt the channel by sending a control frame to the second device.

[0065] Optionally, the receiving address in the first frame may indicate the address of the first device, for example, the MAC address of the first device, or may indicate the address of the second device, for example, the MAC address of the second device. For example, the RA field in FIG. 8 may indicate the address of the first device or the address of the second device.

[0066] It can be understood that the CTS frame shown in Figure 8 is used merely as an embodiment of the first frame and is not used as a restriction on the first frame. Alternatively, the first frame can be another control frame that does not need to be returned in an acknowledgement frame.

[0067] As another example, the first frame may be a data frame. The data frame may include an acknowledgement frame indicator field (ACK policy), which may indicate that an acknowledgement frame does not need to be returned. Figure 9 is a diagram of a possible first frame structure according to one embodiment of the present application. As shown in Figure 9, the first frame may include a frame control field, a duration field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an address 4 field, a quality of service (QoS) control field, a high throughput control (HT control) field, a frame body field, and an FCS field.

[0068] In the data frame shown in FIG. 9, the QoS control field may include an acknowledgement frame indicator field, which may indicate that the first frame does not need to be returned with an acknowledgement frame. For example, the acknowledgement frame indicator field may be 1-bit information. When the acknowledgement frame indicator field has a value of 1, it indicates that the first frame needs to be returned with an acknowledgement frame; when the acknowledgement frame indicator field has a value of 0, it indicates that the first frame does not need to be returned with an acknowledgement frame. Alternatively, when the acknowledgement frame indicator field has a value of 0, it indicates that the first frame needs to be returned with an acknowledgement frame; when the acknowledgement frame indicator field has a value of 1, it indicates that the first frame does not need to be returned with an acknowledgement frame.

[0069] Optionally, the receiving address in the first frame may indicate the address of the first device, e.g., the MAC address of the first device, or may indicate the address of the second device, e.g., the MAC address of the second device. For example, the address4 field in FIG. 9 may indicate the address of the first device or the address of the second device.

[0070] 9 is used merely as an example of the first frame and is not used as a restriction on the first frame. Alternatively, the first frame may be another data frame that does not need to be returned in an acknowledgement frame.

[0071] The first frame in this embodiment of the present application may be a frame or a frame sequence, which may include multiple frames.

[0072] S702: If the first device detects that the channel state is idle, it transmits a second frame after waiting for a first duration.

[0073] The second frame in this embodiment of the present application may be one frame or a frame sequence. The frame sequence may include multiple frames. Optionally, the first device may detect whether the channel state is idle through CCA.

[0074] The second frame mentioned above may be a data frame, i.e., a data frame of a service of the first device, for example, a data frame of a low latency service. The first duration may be predefined or preconfigured in the protocol and is not specifically limited in the present application. For example, the first duration may be set to be less than or equal to a PIFS, for example, less than or equal to 25 microseconds, or the first duration may be set to be a SIFS, for example, 16 microseconds.

[0075] In S702, the first device may perform channel listening and transmit a second frame after determining that the duration of the channel being idle has reached a first duration. It can be understood that the manner in which the first device performs channel listening is not limited in this embodiment of the present application.

[0076] 10A is a scenario diagram of a data transmission method according to an embodiment of the present application. As shown in FIG. 10A, an AP may transmit a first frame without performing channel listening. After transmitting the first frame, the AP may perform channel listening and transmit a second frame after the duration of channel idle reaches a first duration.

[0077] Optionally, after a service, such as a low latency service, arrives at an AP, the AP may wait a specified duration before transmitting the first frame, as shown in Figure 10A. It may be understood that the specified duration may be predefined or preconfigured in the protocol. For example, the specified duration may be set to be less than or equal to a PIFS, e.g., less than or equal to 25 microseconds, or the specified duration may be set to a SIFS, e.g., 16 microseconds, or the specified duration may be set to 0 microseconds.

[0078] Based on the above solution, the first device does not need to perform channel listening when transmitting a first frame. Therefore, the first device may preempt the channel. If the channel state is idle, the first device may wait for a first duration before transmitting a second frame. Therefore, the first device may avoid collision of the second frame and reduce or avoid loss of the second frame. If data is being transmitted on the channel, the first frame may interrupt the data transmission to protect the second frame of the low latency service, thereby reducing or avoiding frame loss caused by collision of the second frame.

[0079] 10B is a diagram of a data transmission method according to one embodiment of the present application. As shown in FIG. 10B, an AP may perform channel listening and transmit a first frame after the channel has remained idle for a specified duration. After transmitting the first frame, the AP may perform channel listening and transmit a second frame after the duration the channel has been idle reaches the first duration.

[0080] Optionally, after a service, such as a low latency service, arrives at the AP, the AP may wait a specified duration before transmitting the first frame, as shown in Figure 10B. It may be understood that the specified duration may be predefined or preconfigured in the protocol. For example, the specified duration may be set to be less than or equal to a PIFS, e.g., less than or equal to 25 microseconds, or the specified duration may be set to a SIFS, e.g., 16 microseconds, or the specified duration may be set to 0 microseconds.

[0081] Based on the above solution, a first device may transmit a first frame when the channel state is idle, thus preempting an idle channel. If the channel state is idle, the first device may wait a first duration before transmitting a second frame. In this way, the first device may avoid collision of the second frame and reduce or avoid loss of the second frame. If data is being transmitted on the channel, the first frame may interrupt the data transmission to protect the second frame of the low latency service, thereby reducing or avoiding frame loss caused by collision of the second frame.

[0082] In a possible case, the first frame may implement rapid channel preemption. See FIG. 11A. The AP may transmit the first frame. For example, after a low-latency service arrives at the AP, the AP may transmit the first frame. Optionally, the AP may wait a specified duration (XIFS) before transmitting the first frame. From FIG. 11A, it can be seen that nodes other than the AP are not transmitting data, i.e., the channel state is idle. The AP may perform channel listening after transmitting the first frame. If it detects that the channel state is idle, the AP may wait a first duration before transmitting a second frame, e.g., a service packet of a low-latency service. Optionally, STA1 may receive the second frame from the AP and transmit an acknowledgement frame (ACK) for the second frame to the AP after SIFS.

[0083] See Figure 11B. The AP may transmit the first frame. For example, the AP may transmit the first frame if it determines that the channel condition is idle. Optionally, the AP may transmit the first frame if the duration during which the channel is idle reaches a specified duration. The AP may perform channel listening after transmitting the first frame. If it detects that the channel condition is idle, the AP may wait for the first duration and then transmit a second frame, for example, a service packet of a low latency service. Optionally, STA1 may receive the second frame from the AP and transmit an ACK for the second frame to the AP after SIFS.

[0084] 11A and 11B, when the AP transmits the first frame, background STA1 determines that the channel state is busy, so it does not perform random backoff and waits for the channel state to become idle before performing random backoff. For example, background STA1 is at time t1 and detects that the channel state is idle. Therefore, the background STA may perform random backoff after waiting DIFS during which the channel is idle. At time t2, background STA1 completes random backoff, the random backoff count value is 0, and background STA1 may transmit a background service packet. Background STA2 receives a background service packet from background STA1 and transmits a background ST packet after SIFS. A1 An acknowledgement frame may be sent for the background service packet.

[0085] From Figure 11A, it can be seen that the AP may transmit the first frame without performing channel listening and may first preempt the channel if the channel is idle. If the AP detects that the channel state is idle, , wait for the first duration and then send the second frame. Therefore, collisions of the second frame may be reduced or avoided, and reliable transmission of the second frame may be implemented.

[0086] From Figure 11B, it can be seen that the AP may transmit the first frame if the channel condition is idle, and may preempt the channel first if the channel is idle. If the AP detects that the channel condition is idle, , wait for the first duration and then send the second frame. Therefore, collisions of the second frame may be reduced or avoided, and reliable transmission of the second frame may be implemented.

[0087] Optionally, to protect reliable transmission of the second frame, the first frame may include a first duration field. The first duration field may indicate a second duration, and the second frame may be transmitted within the second duration. For example, as shown in FIG. 9, the second duration may be indicated in the duration field. The start time of the second duration may be the start time of the first frame, and the end time of the second duration may be the start time of the second frame.

[0088] FIG. 12 is a diagram illustrating a scenario of data transmission according to an embodiment of the present application. An AP may transmit a first frame. For example, after a low latency service arrives at the AP, the AP may transmit the first frame. Optionally, the AP may transmit the first frame after waiting a specified duration (XIFS). As another example, the AP may transmit the first frame if it determines that the channel condition is idle. Optionally, the AP may transmit the first frame if the duration during which the channel is idle reaches a specified duration. The first frame may include a duration field, which indicates a second duration, for example, the duration between tA and tB shown in FIG. 12. Since the receiving address in the first frame is the address of STA3, it can be understood that STAs other than STA3, such as background STA1 and background STA2, cannot access the channel during the second duration. For example, background STA1 receives a first frame and determines that the receiving address in the first frame is not the receiving address of background STA1 and that the duration field in the first frame indicates a second duration, i.e., a duration between tA and tB. Therefore, background STA1 cannot access the channel within the second duration, i.e., background STA1 cannot transmit a service packet within the second duration. Similarly, background STA2 cannot access the channel within the second duration. If the AP detects that the channel state is idle, it may wait for the first duration and then transmit a second frame, e.g., a service packet of a low latency service, at time tB.

[0089] 12, it can be seen that the first frame may indicate a second duration by using a first duration field, and nodes other than the node indicated by the receiving address cannot access the channel within the second duration. Therefore, the reliability of the second frame may be improved, and the probability of collision of the second frame may be reduced.

[0090] In another possible case, assuming that a service packet is being transmitted over the air interface, i.e., when the channel condition is busy, the first frame may interrupt the transmission of the service packet over the air interface. A greedy terminal is used as an example for illustration.

[0091] FIG. 13 is a scenario diagram of a data transmission method according to an embodiment of the present application. From FIG. 13, it can be seen that background STA1 may transmit a frame based on the characteristics of the burst sequence. The AP may transmit the first frame. Optionally, the AP may wait for a specified duration (XIFS) before transmitting the first frame. When transmitting the first frame, the AP does not need to perform channel listening. From FIG. 13, it can be seen that the first frame collides with the frame of background STA1. Therefore, background STA2 cannot receive the frame from background STA1, and therefore background STA2 does not transmit an acknowledgement frame to background STA1. Therefore, background STA1 does not receive an acknowledgement frame from the AP. A1 is If no acknowledgement frame is received within a pre-configured duration, the background ST A1 is , the wait for the acknowledgement frame is considered to have timed out. A1 is , random backoff is performed again and the frame where the collision occurred is retransmitted. A1 isWhen waiting for the acknowledgement frame, the AP detects that the channel condition is idle, and therefore the AP may transmit the second frame after waiting the first duration during which the channel is idle.

[0092] It should be noted that the preset duration may be predefined or preconfigured in the protocol. For example, the preset duration may be set to 50 microseconds. It may be understood that if the AP transmits the first frame without performing channel listening, the transmission of the service packet on the air interface may be interrupted as shown in Figure 13. If the AP performs channel listening and transmits the first frame when the channel state is idle, the first frame cannot interrupt the transmission of the service packet on the air interface.

[0093] The embodiment shown in Figure 13 is explained by using an example in which the first frame interrupts the service packet of the greedy terminal. The first frame provided in this embodiment of the present application can not only interrupt the service packet of the greedy terminal, but also interrupt the service packet of another node. Figure 14 is a scenario diagram of a data transmission method according to an embodiment of the present application.

[0094] Background STA1 performs channel listening and determines that the channel state is idle. Therefore, background STA1 may perform random backoff at time t1 after the duration during which the channel is idle reaches DIFS, and then transmit a background service packet at time t2. The AP transmits a first frame at time t2. That is, the first frame collides with the background service packet transmitted by background STA1. Therefore, background STA2 cannot correctly receive the background service packet from background STA1 and does not transmit an acknowledgment frame to background STA1. Therefore, after waiting for the acknowledgment frame to time out, background STA1 performs random backoff again to access the channel. While background STA1 waits for the acknowledgment frame, the AP may perform channel listening. Because no data is transmitted on the channel, the AP may determine that the channel state is idle. The AP may transmit a second frame after waiting for the first duration. Optionally, STA3 may receive the second frame from the AP and transmit an acknowledgment frame for the second frame to the AP after SIFS.

[0095] After STA3 transmits an acknowledgment frame to the AP, background STA1 may detect that the channel condition is idle. Therefore, background STA1 may perform random backoff after the duration that the channel is idle reaches DIFS. At time t3, the random backoff is completed and the interrupted background service packet is retransmitted. In the embodiment shown in FIG. 14, before transmitting the first frame, regardless of whether the first device performs channel listening, transmission of the service packet on the air interface can be interrupted and the channel can be preempted.

[0096] 13 and 14, it can be seen that the AP may use the first frame to interrupt the transmission of a service packet on the air interface. After the first frame collides with the service packet on the air interface, the transmitting end and the receiving end consider the currently exchanged frame to be lost. Therefore, the transmitting end performs a random backoff again to access the channel. Therefore, the AP may obtain a transmission opportunity for the subsequent second frame by using the first frame.

[0097] In the embodiment shown in FIG. 7 and FIG. 8, the second device may transmit an acknowledgement frame for the second frame to the first device. Optionally, the second device may alternatively transmit a fourth frame to the first device. In a possible example, the second frame may include a second duration field (duration field shown in FIG. 9). The second duration field may indicate a third duration, and the fourth frame may be transmitted within the third duration. The fourth frame described above may be transmitted by the second device. The first It can be understood as a service packet sent to a device.

[0098] FIG. 15A is a scenario diagram of a data transmission method according to an embodiment of the present application. An AP may transmit a first frame. For example, after a low-latency service arrives at the AP, the AP may transmit the first frame. Optionally, the AP may wait a specified duration (XIFS) before transmitting the first frame. The AP may perform channel listening after transmitting the first frame. If the AP detects that the channel state is idle, the AP may wait the first duration before transmitting a second frame, e.g., a service packet of a low-latency service. The second frame may include a second duration field. The second duration field may indicate a third duration. Since the receiving address in the second frame is the address of the receiving end of the second frame, e.g., the address of STA2, it can be understood that nodes other than STA2, such as background STAs, cannot access the channel within the third duration. For example, the background STA1 receives the second frame and determines that the receiving address in the second frame is not the receiving address of the background STA1, and the duration field in the second frame indicates a third duration, so the background STA1 cannot access the channel during the third duration, i.e., the background STA1 cannot transmit a service packet during the third duration.

[0099] ST A2 is , may transmit a fourth frame, for example, a service packet of an uplink service, to the AP within the third duration. A2 is Alternatively, the AP may transmit an acknowledgement frame within a third duration.

[0100] 15B is a scenario diagram of a data transmission method according to an embodiment of the present application. An AP may transmit a first frame. For example, after a low-latency service arrives at the AP, the AP may perform channel listening and transmit the first frame if the channel state is idle. Optionally, the AP may transmit the first frame if the duration during which the channel is idle reaches a specified duration. The AP may perform channel listening after transmitting the first frame. If the AP detects that the channel state is idle, it may wait for the first duration and then transmit a second frame, for example, a service packet of the low-latency service. The second frame may include a second duration field. The second duration field may indicate a third duration. Since the receiving address in the second frame is the address of the receiving end of the second frame, for example, the address of STA2, it can be understood that nodes other than STA2, such as background STAs, cannot access the channel within the third duration. For example, the background STA1 receives the second frame and determines that the receiving address in the second frame is not the receiving address of the background STA1, and the duration field in the second frame indicates a third duration, so the background STA1 cannot access the channel during the third duration, i.e., the background STA1 cannot transmit a service packet during the third duration.

[0101] ST A2 is , may transmit a fourth frame, for example, a service packet of an uplink service, to the AP within the third duration. A2 is Alternatively, the AP may transmit an acknowledgement frame within a third duration.

[0102] It may be appreciated that the second frame may alternatively not need to be returned in an acknowledgement frame, as shown in FIG. 15C.

[0103] From Figures 15A to 15C, it can be seen that the second duration field in the second frame may indicate the third duration, and STA3 may transmit a service packet to the AP within the third duration, thus reserving the channel and reducing the possibility of collision in the fourth frame.

[0104] It should be noted that the STAs in Figures 10A to 15C, such as background STA1, background STA2, and STA3, may be STAs associated with an AP in a local cell or STAs associated with an AP in a same-frequency neighboring cell. Furthermore, the APs, STAs, and background STAs shown in Figures 10A to 15C are shown as examples only. Without loss of generality, the data transmission method provided in this embodiment of the present application may be applied to any Wi-Fi device.

[0105] The technical solutions provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings. Please refer to Figure 16. There is an AP in a local cell, and the AP is associated with a low latency service receiving end (low latency STA) and a background STA. In the following, an example in which the first duration is PIFS and the specified duration is PIFS is used for explanation. In the following embodiments shown in Figures 17 to 21, both the background STA and the low latency STA are associated with the AP in the local cell.

[0106] See Figure 17. Background ST A isis transmitting background service packets on the channel. In this case, for the service packets of the AP and the background STA, the timing can only start after the transmission of the current background service packet has ended, that is, after the AP has transmitted an ACK frame for the background service packet to the background STA. According to the standard, the background STA can only start a random backoff and then transmit the next frame after waiting for at least DIFS = 34 μs while the channel is idle. Optionally, after determining that the duration for which the channel is idle has reached the DIFS duration, the background STA does not have to perform a random backoff to transmit the frame. However, the AP can transmit the first frame after waiting only for PIFS, or the AP can perform channel listening and transmit the first frame after the duration for which the channel is idle has reached PIFS, where PIFS < DIFS. Therefore, the waiting duration of the AP is less than that of the background STA. Therefore, the AP can transmit the first frame before the background STA.

[0107] In one example, the first frame may include a first duration field, and the first duration field indicates a second duration. When detecting that the channel state is idle, the AP may transmit the second frame after waiting only for PIFS.

[0108] Optionally, in the embodiment shown in FIG. 17, the AP may not send an ACK to the background STA. See FIG. 18. After receiving a frame from the background STA, the AP either does not send an ACK to the background STA and waits PIFS before transmitting the first frame, or performs channel listening and transmits the first frame after the duration the channel is idle reaches PIFS. Because the background STA does not receive an ACK from the AP, the background STA may consider the frame lost. Therefore, after waiting for the ACK to time out, the background STA performs random backoff again to access the channel. However, the AP may preempt the channel by using the first frame and reserve a time window for the second frame by using the first duration field, reducing the possibility of collision of the second frame.

[0109] See Figure 19. The AP transmits the first frame. Either the background STA has just completed its random backoff at this point, or the background STA A isIf the AP determines that the duration the channel is idle has just reached DIFS, the background STA transmits a frame. Therefore, the first frame collides with the frame transmitted by the background STA. Wi-Fi is a time division duplex (TDD) system, and transmit and receive modes are not enabled simultaneously. Therefore, when transmitting the first frame, the AP cannot receive the frame from the background STA and therefore does not send an ACK to the background STA. After waiting for the ACK to time out, the background STA performs random backoff again to retransmit the frame where the collision occurred. After detecting that the channel is idle, the AP may transmit the second frame of the low-latency service after waiting PIFS. Based on the embodiments shown in FIGS. 17 to 19, the AP may reduce the probability of collision in one transmission by using the first frame and protect the second frame by sacrificing the first frame or using the first duration field in the first frame, thereby ensuring the transmission of the low-latency service.

[0110] 17 to 19 illustrate a scenario in which a background STA associated with an AP in a local cell is a protocol-compliant standard STA. Referring to Figures 20 and 21, the following describes a scenario in which an AP aborts a burst for a greedy terminal based on the first frame when a background STA associated with an AP in a local cell is a greedy terminal.

[0111] Please refer to FIG. 20. After receiving a background service packet from a background STA, the AP may send an ACK to the background STA. The AP may send the first frame after waiting only for the PIFS. After receiving the ACK from the AP, the background STA waits only for the SIFS during which the channel is idle and then sends the background service packet. Since SIFS < PIFS, the first frame collides with the background service packet of the background STA. Wi-Fi is a TDD system, and the transmit and receive modes are not enabled simultaneously. At this point, the AP is already in the transmit state and thus cannot receive the background service packet. Therefore, the AP does not send an ACK to the background STA. In this case, after waiting for the ACK to timeout, the background STA assumes that the background service packet is lost and retransmits the background service packet. The background STA may perform a random backoff after the channel remains idle for only the AIFS and then retransmit the background service packet.

[0112] After sending the first frame, the AP performs channel listening and sends the second frame after the channel remains idle for only the PIFS. Since PIFS is less than the preset duration for which the background STA waits, the waiting duration DIFS of another device is greater than PIFS, and reliable transmission of the second frame without collision can be ensured. It can be understood that if the AP sends the first frame without performing channel listening, the transmission of the service packet on the air interface may be interrupted as shown in FIG. 20. If the AP performs channel listening and the channel state is idle and then sends the first frame, the first frame cannot interrupt the transmission of the greedy terminal.

[0113] Optionally, the AP may not send an ACK for the burst sequence. See FIG. 21. After receiving a background service packet from a background STA, the AP does not send an ACK to the background STA. The AP may wait a PIFS before transmitting the first frame. Thus, the AP may preempt the channel by using the first frame. Because the AP does not send an ACK to the background STA, after waiting for the ACK to time out, the background STA considers the background service packet to be lost and retransmits the background service packet.

[0114] The first frame includes a first duration field, which indicates a second duration. Therefore, after receiving the first frame, background STAs remain silent and do not access the channel within the second duration. The AP transmits the second frame after the channel has remained idle for a PIFS. Because devices other than the AP do not access the channel within the second duration, collision-free transmission of the second frame can be ensured.

[0115] Based on the embodiments shown in Figures 20 and 21, the AP may reduce the probability of collision in one transmission by using the first frame, and protect the second frame by sacrificing the first frame or using the first duration field in the first frame, thereby ensuring the transmission of low latency services.

[0116] 20 and 21, the problem that the greedy terminal occupies the air interface for a long time and does not release the air interface is avoided, and the burst sequence is interrupted by using the first frame, so that the low latency service can be transmitted in a timely manner, thereby reducing the latency. Compared with the waiting duration in the solution shown in Fig. 20, it can be seen that the waiting duration in the solution shown in Fig. 21 is shorter by the length of one frame, and the latency is shorter.

[0117] 16 to 21 are explained by using an example in which a background STA is associated with an AP in a local cell. With reference to FIGS. 22 to 26, the following describes a scenario in which a background STA is associated with an AP in the same frequency cell.

[0118] Please refer to Figure 22. AP1 exists in the local cell, and AP1 is associated with a low-latency service receiving end, i.e., a low-latency STA. Furthermore, a co-frequency cell exists near the local cell, and background STAs are associated with AP2 in the co-frequency cell. In the following, an example in which the first duration is PIFS and the specified duration is PIFS is used for explanation. In the following embodiments shown in Figures 23 to 26, all background STAs are associated with AP2 in the co-frequency cell.

[0119] Please refer to FIG. 23. The background STA is transmitting background service packets on the channel. In this case, for the service packets of AP1, the timing can only start after the transmission of the current background service packet has ended, that is, after AP2 has sent an ACK frame for the background service packet to the background STA. According to the standard, the background STA can only start a random backoff and then transmit the next frame after waiting for at least DIFS = 34 μs while the channel is idle. Optionally, after determining that the duration for which the channel is idle has reached the DIFS duration, the background STA does not have to perform a random backoff to transmit the frame. However, AP1 can transmit the first frame after waiting for only PIFS, or can perform channel listening and transmit the first frame after the duration for which the channel is idle has reached PIFS, where PIFS < DIFS. Therefore, the waiting duration of AP1 is less than that of the background STA. Therefore, AP1 can transmit the first frame before the background STA.

[0120] In one example, the first frame may include a first duration field, and the first duration field indicates a second duration. When detecting that the channel state is idle, AP1 can transmit the second frame after waiting for only PIFS.

[0121] Note that since the background STA is associated with AP2, AP1 cannot request AP2 not to send an ACK to the background STA.

[0122] See Figure 24. AP1 transmits a first frame at time t1. If the background STA has just completed random backoff at this time, or if the background STA determines that the duration during which the channel is idle has just reached DIFS, the background STA transmits a frame. Therefore, the first frame collides with the frame transmitted by the background STA. This affects channel estimation, scrambling code seed acquisition, data balancing, etc., of the frame transmitted by the background STA. Therefore, AP2 fails to decode the frame of the background STA, and the frame is lost. Therefore, AP2 does not transmit an ACK to the background STA. After waiting for the ACK to time out, the background STA performs random backoff again to retransmit the frame where the collision occurred. After detecting that the channel is idle, AP1 may transmit a second frame of the low latency service after waiting PIFS.

[0123] Based on the embodiments shown in Figures 23 and 24, AP1 can reduce the probability of collision in one transmission by using the first frame, and protect the second frame by sacrificing the first frame or using the first duration field in the first frame, thereby ensuring the transmission of low latency services.

[0124] In the embodiments shown in Figures 23 and 24, the background STAs are standard STAs that comply with the protocol. With reference to Figures 25 and 26, the following describes a case in which the AP suspends the burst of a greedy terminal based on the first frame when a background STA associated with a same-frequency neighbor cell AP is a greedy terminal.

[0125] See Figure 25. AP1 performs channel listening, and at this time, a background STA transmits a background service packet to AP2. After AP2 transmits an ACK to the background STA, AP1 may wait a PIFS before transmitting the first frame. After receiving the ACK, the background STA waits a SIFS during which the channel is idle before transmitting the background service packet. Therefore, the first frame collides with the background service packet. This affects the channel estimation, scrambling code seed acquisition, data balancing, etc. performed by AP2 on the background service packet. Therefore, AP2 fails to decode the background service packet and therefore does not transmit an ACK to the background STA. In this case, after waiting for the ACK to time out, the background STA considers the background service packet lost and retransmits the background service packet. The background STA may perform a random backoff after the channel remains idle for an AIFS and then retransmit the background service packet.

[0126] After transmitting the first frame, AP1 performs channel listening and transmits the second frame after the channel remains idle for PIFS, which is less than the preset duration for background STAs to wait, while the waiting duration DIFS of another device is greater than PIFS, ensuring collision-free transmission of the second frame.

[0127] Optionally, AP1 may transmit the first frame after the background STA transmits the background service packet. See FIG. 26. AP1 performs channel listening, and at this point, the background STA transmits the background service packet to AP2. After the background STA transmits the background service packet, AP1 may wait PIFS before transmitting the first frame. After receiving the background service packet from the background STA, AP2 sends an ACK to the background STA. Therefore, the ACK collides with the background service packet. This affects channel estimation, scrambling code seed acquisition performed by the background STA for the ACK, data balancing, etc. Therefore, the background STA fails to decode the ACK. In this case, the background STA fails to receive the ACK. Therefore, the background STA's wait for the ACK times out, and the background STA considers the background service packet lost and retransmits the background service packet. The background STA may perform a random backoff after the channel has remained idle for AIFS and then retransmit the background service packet.

[0128] After transmitting the first frame, AP1 performs channel listening and transmits the second frame after the channel remains idle for PIFS, which is less than the preset duration for background STAs to wait, while the waiting duration DIFS of another device is greater than PIFS, ensuring collision-free transmission of the second frame.

[0129] Based on the embodiment shown in Figures 25 and 26, the problem that a greedy terminal in a same-frequency adjacent cell occupies the air interface for a long time and does not release the air interface is avoided, and the transmission of the burst sequence is interrupted by using the first frame, so that the low-latency service can be transmitted in a timely manner, thereby reducing the latency. In the embodiment shown in Figure 26, it can be seen that the first frame interrupts the ACK sent by AP2. Therefore, the latency is shorter compared with the latency in the embodiment shown in Figure 25. A P1 It can be understood that when transmitting the first frame without performing channel listening, the transmission of the service packet on the air interface may be interrupted as shown in Figures 25 and 26. P1 If a terminal performs channel listening and transmits the first frame when the channel state is idle, the first frame cannot interrupt the transmission of a greedy terminal.

[0130] With reference to the accompanying drawings, the following describes a communication device in an embodiment of the present application, which is configured to implement the above-mentioned method. Therefore, all the above content can be used in the following embodiment. The repeated content will not be described again.

[0131] 27 is a block diagram of a communication device 2700 according to an embodiment of the present application. The communication device 2700 may correspondingly perform functions or steps performed by the first device in the above-described method embodiments. The communication device may include a processing unit 2710 and a transceiver unit 2720. Optionally, a storage unit may be further included. The storage unit may be configured to store instructions (codes or programs) and / or data. The processing unit 2710 and the transceiver unit 2720 may be coupled to the storage unit. For example, the processing unit 2710 may read instructions (codes or programs) and / or data in the storage unit and perform the corresponding method. The above-described units may be independently located or partially or fully integrated.

[0132] In some possible implementations, the communication device 2700 can correspondingly perform the behavior and functions of the first device in the above-described method embodiments. For example, the communication device 2700 may be the first device or a component (e.g., a chip or circuit) used in the first device. The transceiver unit 2720 may be configured to perform all receiving or transmitting operations performed by the first device in the embodiment shown in FIG. 7, e.g., S701 or S702 in the embodiment shown in FIG. 7, and / or support other processes of the techniques described herein. The processing unit 2710 is configured to perform all operations performed by the first device in the embodiment shown in FIG. 7 except for receiving and transmitting operations, and / or support other processes of the techniques described herein.

[0133] The transceiver unit 2720 is configured to transmit a first frame to a second device. The first device does not need to perform channel listening when transmitting the first frame. The processing unit 2710 is configured to detect a channel condition. The transceiver unit 2720 is further configured to transmit a second frame after waiting a first duration if the channel condition is detected to be idle.

[0134] For the operations performed by the processing unit 2710 and the transceiver unit 2720, please refer to the relevant descriptions in the above method embodiments.

[0135] It should be understood that the processing unit 2710 in this embodiment of the present application may be implemented by a processor or processor-related circuit components, and the transceiver unit 2720 may be implemented by a transceiver, transceiver-related circuit components, or a communication interface.

[0136] Based on the same concept, as shown in Figure 28, an embodiment of the present application provides a communication device 2800. The communication device 2800 includes a processor 2810. Optionally, the communication device 2800 may further include a memory 2820 configured to store instructions to be executed by the processor 2810, or to store input data required by the processor 2810 to execute the instructions, or to store data generated after the processor 2810 executes the instructions. The processor 2810 may implement the methods shown in the above-mentioned method embodiments by using the instructions stored in the memory 2820.

[0137] Based on the same concept, as shown in Figure 29, an embodiment of the present application provides a communication device 2900. The communication device 2900 may be a chip or a chip system. Optionally, in this embodiment of the present application, the chip system may include a chip, or may include a chip and another discrete device.

[0138] The communications device 2900 may include at least one processor 2910. The processor 2910 is coupled to a memory. Optionally, the memory may be located internal to the device or external to the device. For example, the communications device 2900 may further include at least one memory 2920. The memory 2920 stores necessary computer programs, configuration information, computer programs or instructions, and / or data for implementing any one of the aforementioned embodiments. The processor 2910 may execute the computer programs stored in the memory 2920 to complete the method in any one of the aforementioned embodiments.

[0139] The coupling in this embodiment of the present application may be an indirect coupling or communication connection between the devices, units, or modules in an electrical, mechanical, or other form, and is used for exchanging information between the devices, units, or modules. The processor 2910 may operate in conjunction with the memory 2920. In this embodiment of the present application, the specific connection medium between the transceiver 2930, the processor 2910, and the memory 2920 is not limited.

[0140] The communication device 2900 may further include a transceiver 2930, and the communication device 2900 may exchange information with another device by using the transceiver 2930. The transceiver 2930 may be a circuit, a bus, a transceiver, or any other device that may be configured to exchange information, or may be referred to as a signal transceiver unit. As shown in FIG. 29, the transceiver 2930 includes a transmitter 2931, a receiver 2932, and an antenna 2933. Furthermore, if the communication device 2900 is a chip-type device or circuit, the transceiver in the communication device 2900 may alternatively be an input / output circuit and / or a communication interface, and may input data (or may be referred to as "receiving data") and output data (or may be referred to as "transmitting data"). The processor may be an integrated processor, a microprocessor, or an integrated circuit, and the processor may determine output data based on the input data.

[0141] In one possible implementation, the communication device 2900 may be used in a first device. Specifically, the communication device 2900 may be the first device or may be a device capable of supporting the first device in performing the functions of the first device in any one of the aforementioned embodiments. The memory 2920 stores necessary computer programs, computer programs or instructions, and / or data for performing the functions of the first device in any one of the aforementioned embodiments. The processor 2910 may execute the computer programs stored in the memory 2920 to complete the method performed by the first device in any one of the aforementioned embodiments.

[0142] The communication device 2900 provided in this embodiment may be used in a first device to complete the method performed by the first device. Therefore, for the technical effects that can be achieved by this embodiment, please refer to the above-mentioned method embodiment. The details will not be described again here.

[0143] In this embodiment of the present application, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component, which may implement or perform the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or any conventional processor, etc. The steps of the methods disclosed with reference to the embodiments of the present application may be performed directly by a hardware processor, or may be performed by using a combination of hardware and software modules in a processor.

[0144] In this embodiment of the present application, the memory may be a non-volatile memory, such as a hard disk drive (HDD) or a solid-state drive (SSD), or a volatile memory, such as a random access memory (RAM). Alternatively, the memory may be any other medium that can be configured to hold or store expected program code in the form of instructions or data structures and that can be accessed by a computer, but is not limited to this. The memory in this embodiment of the present application may alternatively be a circuit or any other device that can perform a storage function and is configured to store computer programs, computer program or instructions, and / or data.

[0145] Based on the aforementioned embodiment, please refer to Fig. 30. An embodiment of the present application further provides another communication device 3000, comprising an input / output interface 3010 and a logic circuit 3020. The input / output interface 3010 is configured to receive code instructions and send the code instructions to the logic circuit 3020. The logic circuit 3020 is configured to execute the code instructions to perform the method performed by the first device in any one of the aforementioned embodiments.

[0146] The following describes in detail the operations performed by a communication unit used in the first device or the second device.

[0147] In an optional implementation, the communication apparatus 3000 may be used in a first device to perform a method performed by the first device, for example, the method may specifically be the method performed by the first device in the embodiment shown in FIG.

[0148] The communication device 3000 provided in this embodiment may be used in a first device to complete the method performed by the first device. Therefore, for the technical effects that can be achieved by this embodiment, please refer to the above-mentioned method embodiment. The details will not be described again here.

[0149] Based on the above-mentioned embodiment, an embodiment of the present application further provides a communication system, which includes at least one communication device used in a first device and at least one communication device used in a second device. For technical effects that can be achieved by this embodiment, please refer to the above-mentioned method embodiment. Details will not be described again here.

[0150] Based on the above embodiment, one embodiment of the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program or instructions. When the instructions are executed, the method performed by the first device or the method performed by the second device in any one of the above embodiments is performed. The computer-readable storage medium may include any medium capable of storing program code, such as a USB flash drive, a removable hard disk drive, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0151] 27 to 30, an embodiment of the present application further provides a chip including a processor configured to support the communication device in performing the functions of the first device or the second device in the above-described method embodiments. In a possible design, the chip is connected to or includes a memory. The memory is configured to store computer programs or instructions and data required for the communication device.

[0152] Those skilled in the art should understand that the embodiments of the present application may be provided as a method, a system, or a computer program product. Therefore, the present application may take the form of a hardware-only embodiment, a software-only embodiment, or an embodiment having a combination of software and hardware. In addition, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0153] The present application will be described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present application. It should be understood that computer programs or instructions may be used to implement each procedure and / or each block of the flowcharts and / or block diagrams, and combinations of procedures and / or blocks in the flowcharts and / or block diagrams. The computer programs or instructions may be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or another programmable data processing device to create a machine, such that the instructions executed by the processor of the computer or another programmable data processing device create an apparatus that implements the functions specified in one or more procedures in the flowcharts and / or in one or more blocks in the block diagrams.

[0154] The computer program or instructions may alternatively be stored in a computer-readable memory capable of directing a computer or another programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable memory generate an artifact comprising an instruction apparatus that performs the functions specified in one or more steps in the flowcharts and / or in one or more blocks in the block diagrams.

[0155] The computer program or instructions may alternatively be loaded onto a computer or other programmable data processing device such that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more procedures of the flowcharts and / or one or more blocks of the block diagrams.

[0156] It is apparent that those skilled in the art can make various modifications and variations to the embodiments of the present application without departing from the scope of the embodiments of the present application. In this case, the present application intends to cover these modifications and variations of the embodiments of the present application as long as they fall within the scope of the claims of the present application and their equivalent techniques. 。 [Other possible items] [Item 1] 1. A data transmission method, comprising: transmitting, by a first device, a first frame to a second device, wherein the first device does not need to perform channel listening when transmitting the first frame; and transmitting, by the first device, a second frame after waiting a first duration if the channel condition is detected to be idle. A method for providing the above. [Item 2] 1. A data transmission method, comprising: transmitting, by a first device, the first frame when detecting that the channel condition is idle; and transmitting, by the first device, a second frame after waiting a first duration if the channel condition is detected to be idle. A method for providing [Item 3] transmitting, by a first device, the first frame when detecting that a channel condition is idle; transmitting, by the first device, the first frame after waiting a specified duration if the channel condition is detected to be idle. Item 3. The method according to item 2, comprising: [Item 4] 4. The method of item 3, wherein the specified duration is less than or equal to PFS. [Item 5] 5. The method of any one of items 1 to 4, wherein the first duration is less than or equal to PIFS. [Item 6] 6. The method of claim 1, wherein the first frame includes a first duration field, the first duration field indicating a second duration, and the second frame is transmitted within the second duration. [Item 7] Prior to the step of transmitting, by the first device, the first frame to the second device, the method further comprises: receiving, by the first device, a third frame from a third device; and skipping, by the first device, transmitting an acknowledgment frame for the third frame. 7. The method of any one of items 1 to 6, further comprising: [Item 8] 8. The method of claim 1, wherein the first frame includes an acknowledgement frame indicator field, and the acknowledgement frame indicator field indicates that the first frame does not need to be returned in an acknowledgement frame. [Item 9] 9. The method of any one of items 1 to 8, wherein the first frame comprises a control frame, or the first frame comprises a data frame. [Item 10] 10. The method of any one of items 1 to 9, wherein the receiving address in the first frame is the address of the first device. [Item 11] After the first device transmits the second frame, the method further comprises: receiving, by the first device, an acknowledgment frame transmitted by the second device for the second frame; and receiving, by the first device, a fourth frame transmitted by the second device, wherein the second frame includes a second duration field, the second duration field indicating a third duration, and the fourth frame being transmitted within the third duration. 11. The method of any one of items 1 to 10, further comprising: [Item 12] A communication device comprising a processing unit and a transceiver unit, The transceiver unit is configured to transmit a first frame to a second device, wherein the first device does not need to perform channel listening when transmitting the first frame; The processing unit is configured to detect a channel; The transceiver unit is further configured to transmit a second frame after waiting a first duration if a channel condition is detected to be idle. device. [Item 13] A communication device comprising a processing unit and a transceiver unit, The processing unit is configured to detect a channel; The transceiver unit is configured to transmit the first frame when a channel condition is detected to be idle; The transceiver unit is further configured to transmit a second frame after waiting a first duration if the channel condition is detected to be idle. device. [Item 14] The transceiver unit specifically comprises: If the channel state is detected as idle, then transmit the first frame after waiting a specified duration. Item 14. The device according to item 13, configured as follows: [Item 15] Item 15. The device of item 14, wherein the specified duration is less than or equal to PFS. [Item 16] 16. The device of any one of items 12 to 15, wherein the first duration is less than or equal to PIFS. [Item 17] 17. The device of claim 12, wherein the first frame includes a first duration field, the first duration field indicating a second duration, and the second frame is transmitted within the second duration. [Item 18] The transceiver unit comprises: Receive a third frame from a third device It is further structured as follows: The processing unit is further configured to determine not to transmit an acknowledgment frame for the third frame. 18. A device according to any one of items 12 to 17. [Item 19] 19. The device of claim 12, wherein the first frame includes an acknowledgement frame indicator field, the acknowledgement frame indicator field indicating that the first frame does not need to be returned in an acknowledgement frame. [Item 20] 20. The device of any one of items 12 to 19, wherein the first frame comprises a control frame, or the first frame comprises a data frame. [Item 21] 21. The device of any one of items 12 to 20, wherein a receiving address in the first frame is an address of the first device. [Item 22] The transceiver unit comprises: receiving an acknowledgment frame transmitted by the second device for the second frame; receiving a fourth frame transmitted by the second device, wherein the second frame comprises a second duration field, the second duration field indicating a third duration, and the fourth frame is transmitted within the third duration; 22. The device of any one of items 12 to 21, further configured to: [Item 23] A communication device comprising a processor and a memory, the memory configured to store computer programs or instructions; The processor is configured to execute the computer program or instructions in the memory so that the device performs the method of any one of items 1 or 5 to 11, or so that the device performs the method of any one of items 2 to 11. Communication equipment. [Item 24] 12. A computer-readable storage medium storing computer-executable instructions that, when invoked by an electronic device, enable the electronic device to perform the method of any one of items 1 or 5 to 11, or enable the electronic device to perform the method of any one of items 2 to 11. [Item 25] 12. A computer program product comprising computer-executable instructions, which, when executed on a computer, enable the computer to perform the method according to any one of items 1 to 11. [Item 26] 1. A chip system comprising: communication interface; and A processor configured to call and execute the instructions by using the communication interface so that a device in which the chip system is installed executes the method according to any one of items 1 or 5 to 11, or a device in which the chip system is installed executes the method according to any one of items 2 to 11. A chip system comprising:

Claims

1. 1. A data transmission method, comprising: transmitting, by a first device, a first frame to a second device, wherein the first device does not need to perform channel listening when transmitting the first frame; and transmitting, by the first device, a second frame after waiting a first duration if the channel condition is detected to be idle; A method for providing the above.

2. 1. A data transmission method, comprising: transmitting, by a first device, the first frame when detecting that the channel condition is idle; and transmitting, by the first device, a second frame after waiting a first duration if the channel condition is detected to be idle; A method for providing the above.

3. transmitting, by a first device, the first frame when detecting that the channel condition is idle; transmitting, by the first device, the first frame after waiting a specified duration if the channel condition is detected to be idle.

3. The method of claim 2, comprising:

4. The method of claim 3 , wherein the specified duration is less than or equal to a PFS.

5. The method of claim 1 , wherein the first duration is less than or equal to a PIFS.

6. 6. The method of claim 1, wherein the first frame includes a first duration field, the first duration field indicating a second duration, and the second frame is transmitted within the second duration.

7. Prior to the step of transmitting, by the first device, the first frame to the second device, the method further comprises: receiving, by the first device, a third frame from a third device; and skipping, by the first device, transmitting an acknowledgement frame for the third frame. The method of claim 1 , further comprising:

8. 8. The method of claim 1, wherein the first frame includes an acknowledgement frame indicator field, the acknowledgement frame indicator field indicating that the first frame does not need to be returned in an acknowledgement frame.

9. The method of claim 1 , wherein the first frame comprises a control frame, or the first frame comprises a data frame.

10. The method of claim 1 , wherein a receiving address in the first frame is an address of the first device.

11. After the first device transmits the second frame, the method further comprises: receiving, by the first device, an acknowledgment frame transmitted by the second device for the second frame; and receiving, by the first device, a fourth frame transmitted by the second device, wherein the second frame includes a second duration field, the second duration field indicating a third duration, and the fourth frame being transmitted within the third duration. The method of claim 1 , further comprising:

12. A communication device comprising a processing unit and a transceiver unit, the transceiver unit is configured to transmit a first frame to a second device, wherein the first device does not need to perform channel listening when transmitting the first frame; The processing unit is configured to detect a channel; The transceiver unit is further configured to transmit a second frame after waiting a first duration if a channel condition is detected to be idle. device.

13. A communication device comprising a processing unit and a transceiver unit, The processing unit is configured to detect a channel; The transceiver unit is configured to transmit the first frame when a channel condition is detected to be idle; The transceiver unit is further configured to transmit a second frame after waiting a first duration if the channel condition is detected to be idle. device.

14. The transceiver unit specifically comprises: If the channel state is detected as idle, then transmit the first frame after waiting a specified duration. The device of claim 13 configured to:

15. The device of claim 14 , wherein the specified duration is less than or equal to a PFS.

16. 16. The device of claim 12, wherein the first duration is less than or equal to a PIFS.

17. 17. The device of claim 12, wherein the first frame includes a first duration field, the first duration field indicating a second duration, and the second frame is transmitted within the second duration.

18. The transceiver unit comprises: Receive a third frame from a third device The method further comprises: The processing unit is further configured to determine not to transmit an acknowledgement frame for the third frame.

18. A device according to any one of claims 12 to 17.

19. 19. The device of claim 12, wherein the first frame includes an acknowledgement frame indicator field, the acknowledgement frame indicator field indicating that the first frame does not need to be returned in an acknowledgement frame.

20. 20. The device of claim 12, wherein the first frame comprises a control frame, or wherein the first frame comprises a data frame.

21. 21. The device of claim 12, wherein a receiving address in the first frame is an address of the first device.

22. The transceiver unit comprises: receiving an acknowledgment frame transmitted by the second device for the second frame; receiving a fourth frame transmitted by the second device, wherein the second frame comprises a second duration field, the second duration field indicating a third duration, and the fourth frame is transmitted within the third duration; 22. The device of claim 12, further configured to:

23. A communication device comprising a processor and a memory, the memory configured to store computer programs or instructions; The processor is configured to execute the computer program or instructions in the memory such that the device performs the method of any one of claims 1 or 5 to 11, or such that the device performs the method of any one of claims 2 to 11. Communication equipment.

24. 12. A computer-readable storage medium storing computer-executable instructions that, when invoked by an electronic device, enable the electronic device to perform the method of claim 1 or any one of claims 5 to 11, or enable the electronic device to perform the method of claim 2.

25. 12. A computer program product comprising computer-executable instructions, which when executed on a computer enable the computer to carry out the method of any one of claims 1 to 11.

26. 1. A chip system comprising: a communication interface; and A processor configured to call and execute the instructions by using the communication interface so that a device in which the chip system is installed executes the method of any one of claims 1 or 5 to 11, or a device in which the chip system is installed executes the method of any one of claims 2 to 11. A chip system comprising:

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