Communication method and communication device

Abstract

A communication method and a communication device, which can be applied to a WLAN system supporting 802.11 series protocols, for example, IEEE 802.11ax next-generation Wi-Fi protocols, such as 802.11be, 802.11bn, and 802.11bn next-generation, and can also be applied to UWB-based wireless personal area network systems and sensing systems. In the method, a first access point sends a first PPDU, and a second access point sends a second PPDU, wherein a first sequence that is carried in a first LTF in the first PPDU and used by a first station to perform channel estimation and a second sequence that is carried in a second LTF in the second PPDU and used by a second station to perform channel estimation are different sequences. In this way, correlated interference during multi-AP coordination can be reduced, and the accuracy of channel estimation of a receiving end can be improved.

Description

A communication method and a communication device

[0001] This application claims priority to Chinese Patent Application No. 202510229262.3, filed on February 27, 2025, entitled "A Communication Method and Communication Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communications, and more specifically, to a communication method and a communication device. Background Technology

[0003] With the development of wireless networks and the increasing popularity of wireless local area network (WLAN) technology, WLAN devices are becoming increasingly dense. Because access points (APs) are easy to deploy, the growing density of APs also brings more interference.

[0004] How to reduce interference and improve the quality of service for users through cooperation between access points (APs) is a problem that next-generation WLAN technology needs to consider. Summary of the Invention

[0005] This application provides a communication method and communication device that can reduce mutual interference when multiple APs cooperate and improve the accuracy of channel estimation.

[0006] In a first aspect, a communication method is provided, which can be applied to a first access point, for example, can be executed by the first access point or by a component of the first access point (e.g., a chip, circuit, or chip system).

[0007] The method includes: sending a physical protocol data unit (PPDU) to a second access point, wherein the first PPDU includes a first long training field (LTF), the first LTF is used to carry a first sequence, the first sequence is used by the first site for channel estimation, the first sequence is different from the second sequence, the second sequence is used by the second site for channel estimation, the second sequence is carried in the second LTF of the second PPDU, the second PPDU is a PPDU sent by the second access point to the second site, and the first LTF and the second LTF occupy the same time-frequency resources; and sending the first PPDU to the first site.

[0008] Based on the above scheme, when the first LTF in the first PPDU and the second LTF in the second PPDU occupy the same time-frequency resources, for example, in a multi-AP cooperative process, the first sequence carried in the first LTF for channel estimation at the first site and the second sequence carried in the second LTF for channel estimation at the second site are different sequences. Since these different sequences have different frequency and phase characteristics, signals from different devices can be distinguished during channel estimation at the receiver, thereby reducing mutual interference. In other words, it can reduce correlation interference during multi-AP cooperation and improve the accuracy of channel estimation at the receiver.

[0009] In this application, the first access point and the second access point are different access points in a multi-AP coordination (MAPC) process. The multi-AP coordination process can be a coordinated spatial reuse (Co-SR or CSR) process or a coordinated beamforming (Co-BF) process. The first access point can be the primary access point, and the second access point can be the secondary access point.

[0010] In conjunction with the first aspect, in some implementations, the first sequence and the second sequence are orthogonal, that is, the first sequence and the second sequence are orthogonal to each other.

[0011] Since the inner product between two orthogonal sequences is zero or a negative multiple of the sequence length, interference between different sequences can cancel each other out. In this application, the first sequence used for channel estimation at the first site and the second sequence used for channel estimation at the second site are orthogonal. Therefore, mutual interference when two access points cooperate can be reduced, and the accuracy of channel estimation can be improved.

[0012] For example, the fact that the first LTF and the second LTF occupy the same time-frequency resources can mean that: the guard interval (GI) of the symbols carrying the first sequence is the same as the GI of the symbols carrying the second sequence, the number of symbols carrying the first sequence is the same as the number of symbols carrying the second sequence, the number of subcarriers corresponding to the symbols carrying the first sequence is the same as the number of subcarriers corresponding to the symbols carrying the second sequence, and the subcarrier spacing of the subcarriers corresponding to the symbols carrying the first sequence is the same as the subcarrier spacing of the subcarriers corresponding to the symbols carrying the second sequence.

[0013] In conjunction with the first aspect, in some implementations, before generating the first PPDU, the method further includes: sending a first frame to a second access point, the first frame including first indication information, the first indication information being used to indicate that the sequence carried by the second LTF is orthogonal to the first sequence.

[0014] Based on the above scheme, the first access point can indicate the characteristics of the sequence carried by the second LTF to the second access point, thus achieving orthogonality between the first sequence and the second sequence.

[0015] The sequences orthogonal to the first sequence include the second sequence.

[0016] For example, the first indication information includes at least one of the following: the guard interval of the symbols carrying the second sequence, the number of subcarriers corresponding to the symbols carrying the second sequence, the number of symbols carrying the second sequence, the subcarrier spacing of the subcarriers corresponding to the symbols carrying the second sequence, and the starting row index of the coefficients used to generate the second sequence in the P matrix.

[0017] Based on the above scheme, the first access point can indicate the detailed parameters of the sequence carried by the second LTF to the second access point, which helps the second access point to determine the second sequence.

[0018] Optionally, the starting row index of the coefficients used to generate the second sequence in the P matrix can be indicated by the spatial stream number corresponding to the first PPDU. The starting row index of the coefficients used to generate the second sequence in the P matrix can be understood as the row number in the P matrix from which the second sequence is generated.

[0019] In this application, the number of symbols carrying the first sequence is determined based on the number of spatial streams corresponding to the first PPDU and the number of spatial streams corresponding to the second PPDU.

[0020] In conjunction with the first aspect, in some implementations, before sending the first frame to the second access point, the method further includes: receiving a second frame from the second access point, the second frame being used to indicate parameters of the sequence carried by the second LTF.

[0021] Based on the above scheme, the second access point can indicate the parameters of the sequence it needs to the first access point. This helps the first node and the second access point to negotiate and determine the LTF sequence, so as to reduce interference and improve the accuracy of channel estimation.

[0022] For example, the second frame is a Co-SR response frame or a Co-BF response frame. The second frame can be used to determine the first indication information.

[0023] Optionally, the second frame includes third indication information, which indicates whether the second access point requests the spatial stream number corresponding to the second PPDU.

[0024] Based on the above scheme, the second access point can indicate to the first access point whether it needs to determine the number of spatial streams corresponding to the second PPDU itself, which can provide the second access point with greater freedom and higher flexibility.

[0025] Optionally, the first frame also includes fourth indication information, which is used to indicate that the second access point does not need to perform the interference zeroing precoding strategy.

[0026] Based on the above scheme, since the first sequence and the second sequence are orthogonal, the purpose of interference cancellation can be achieved. That is, there is no need to perform interference zeroing. Interference can be eliminated by using mutually orthogonal sequences. Therefore, in the Co-BF transmission scenario, the first access point can instruct the second access point not to perform interference zeroing when performing precoding, thereby reducing the implementation complexity of the second access point.

[0027] In conjunction with the first aspect, in some implementations, both the first sequence and the second sequence are pseudo-random sequences.

[0028] Based on the above scheme, the probability of the first access point and the second access point using the same LTF sequence can be reduced, thereby reducing interference between the two access points.

[0029] In conjunction with the first aspect, in some implementations, before generating the first PPDU, the method further includes: sending a first frame to a second access point, the first frame including second indication information, the second indication information being used to indicate that the sequence carried by the second LTF is a pseudo-random sequence.

[0030] Based on the above scheme, the first access point can indicate the characteristics of the sequence carried by the second LTF to the second access point, which helps the second access point to determine the second sequence.

[0031] For example, the first sequence is generated based on the color of the first basic service set (BSS) to which the first access point belongs, and the second sequence is generated based on the color of the second BSS to which the second access point belongs.

[0032] Since the first access point and the second access point belong to different BSSs, the generated first sequence and second sequence can also be different, thereby reducing interference.

[0033] In conjunction with the first aspect, in some implementations, the first frame is used to initiate the negotiation process for multi-AP cooperation; for example, the first frame is a Co-SR request frame or a Co-BF request frame. Alternatively, the first frame is used to initiate the transmission process for multi-AP cooperation; for example, the first frame is a Co-SR trigger frame or a Co-BF trigger frame.

[0034] Secondly, a communication method is provided, which can be applied to a second access point, for example, it can be executed by the second access point or by a component of the second access point (e.g., a chip, circuit, or chip system).

[0035] The method includes: generating a second PPDU, the second PPDU including a second LTF, the second LTF being used to carry a second sequence, the second sequence being used by a second site for channel estimation, the second sequence being different from a first sequence, the first sequence being used by a first site for channel estimation, the first sequence being carried in a first LTF in a first PPDU, the first PPDU being a PPDU sent from a first access point to a first site, the first LTF and the second LTF occupying the same time-frequency resources; and sending the second PPDU to the second site.

[0036] The first access point can be the primary access point, and the second access point can be the secondary access point.

[0037] In conjunction with the second aspect, in some implementations, the first sequence and the second sequence are orthogonal.

[0038] In conjunction with the second aspect, in some implementations, before generating the second PPDU, the method further includes: receiving a first frame from a first access point, the first frame including first indication information, the first indication information being used to indicate that the sequence carried by the second LTF is a sequence orthogonal to the first sequence.

[0039] In conjunction with the second aspect, in some implementations, before receiving the first frame from the first access point, the method further includes: sending a second frame to the first access point, the second frame being used to indicate parameters of the sequence carried by the second LTF.

[0040] In conjunction with the second aspect, in some implementations, both the first and second sequences are pseudo-random sequences.

[0041] In conjunction with the second aspect, in some implementations, before generating the second PPDU, the method further includes: receiving a first frame from a first access point, the first frame including second indication information, the second indication information being used to indicate that the sequence carried by the second LTF is a pseudo-random sequence.

[0042] For example, the first sequence is generated based on the first BSS color to which the first access point belongs, and the second sequence is generated based on the second BSS color to which the second access point belongs.

[0043] Thirdly, a communication method is provided, which can be applied to a first access point, for example, can be executed by the first access point or by a component of the first access point (e.g., a chip, circuit, or chip system).

[0044] The method further includes: generating a first PPDU, the first PPDU including a first LTF, the first LTF being used to carry a first sequence, the first sequence being used by a first site for channel estimation, the first LTF and the second LTF in the second PPDU not overlapping in the time domain, the first LTF and the second LTF in the second PPDU occupying the same frequency domain resources, the second LTF carrying a second sequence, the second sequence being used by a second site for channel estimation, the second PPDU being a PPDU sent from a second access point to a second site, the first access point and the second access point being different access points in the multi-AP cooperation process; and sending the first PPDU to the first site.

[0045] In the above scheme, when the second LTF in the first LTF and the second PPDU occupy the same frequency domain resources, since they do not overlap in the time domain, there will be no interference regardless of whether the first sequence and the second sequence are the same. In other words, this scheme can reduce mutual interference when multiple APs cooperate and improve the accuracy of channel estimation.

[0046] In conjunction with the third aspect, in some implementations, the first access point is the primary access point, and the second access point is the secondary access point.

[0047] In conjunction with the third aspect, in some implementations, the first access point is the secondary access point, and the second access point is the primary access point.

[0048] For example, both the first sequence and the second sequence are LTF sequences.

[0049] Fourthly, a communication method is provided, which can be applied to a first access point and a second access point, for example, it can be performed by the first access point and the second access point, or by components of the first access point and the second access point (e.g., chips, circuits, or chip systems).

[0050] The method further includes: a first access point sending a first PPDU to a first site, the first PPDU including a first LTF, the first LTF carrying a first sequence, the first sequence being used by the first site for channel estimation; and a second access point sending a second PPDU to a second site, the second PPDU including a second LTF, the second LTF carrying a second sequence, the second sequence being used by the second site for channel estimation. The first LTF and the second LTF occupy the same time-frequency resources, and the first sequence and the second sequence are different. Alternatively, the first LTF and the second LTF do not overlap in the time domain, and the second LTF in the first LTF and the second PPDU occupy the same frequency domain resources.

[0051] Fifthly, a communication device is provided, which can be a first access point or a component of the first access point (e.g., a chip, circuit, or chip system). The device can have the functions described in the first aspect. For example, the device includes modules, units, or means corresponding to the operations involved in the first aspect. These modules, units, or means can be implemented by software, hardware, or a combination of software and hardware.

[0052] Specifically, the device includes: a processing unit for generating a first PPDU, the first PPDU including a first LTF, the first LTF carrying a first sequence, the first sequence being used by a first site for channel estimation, the first sequence being different from a second sequence, the second sequence being used by a second site for channel estimation, the second sequence being carried in a second LTF in a second PPDU, the second PPDU being a PPDU sent from a second access point to a second site, the first LTF and the second LTF occupying the same time-frequency resources; and a transceiver unit for sending the first PPDU to the first site.

[0053] In conjunction with the fifth aspect, in some implementations, the first sequence and the second sequence are orthogonal.

[0054] In conjunction with the fifth aspect, in some implementations, before generating the first PPDU, the transceiver unit is further configured to: send a first frame to the second access point, the first frame including first indication information, the first indication information being used to indicate that the sequence carried by the second LTF is a sequence orthogonal to the first sequence.

[0055] In conjunction with the fifth aspect, in some implementations, before sending the first frame to the second access point, the transceiver unit is further configured to: receive a second frame from the second access point, the second frame being used to indicate parameters of the sequence carried by the second LTF.

[0056] In conjunction with the fifth aspect, in some implementations, both the first and second sequences are pseudo-random sequences.

[0057] In conjunction with the fifth aspect, in some implementations, before generating the first PPDU, the transceiver unit is further configured to: send a first frame to the second access point, the first frame including second indication information, the second indication information being used to indicate that the sequence carried by the second LTF is a pseudo-random sequence.

[0058] In a sixth aspect, a communication device is provided. The device can be a second access point or a component of the second access point (e.g., a chip, circuit, or chip system). The device can have the functions described in the second aspect above. For example, the device includes a module, unit, or means corresponding to the operation involved in the second aspect above. The module, unit, or means can be implemented by software, hardware, or a combination of software and hardware.

[0059] Specifically, the device includes: a processing unit for generating a second PPDU, the second PPDU including a second LTF, the second LTF carrying a second sequence, the second sequence being used by a second site for channel estimation, the second sequence being different from a first sequence, the first sequence being used by a first site for channel estimation, the first sequence being carried in a first LTF of a first PPDU, the first PPDU being a PPDU sent from a first access point to a first site, the first LTF and the second LTF occupying the same time-frequency resources; and a transceiver unit for sending the second PPDU to the second site.

[0060] In conjunction with the sixth aspect, in some implementations, the first sequence and the second sequence are orthogonal.

[0061] In conjunction with the sixth aspect, in some implementations, before generating the second PPDU, the transceiver unit is further configured to: receive a first frame from the first access point, the first frame including first indication information, the first indication information being used to indicate that the sequence carried by the second LTF is a sequence orthogonal to the first sequence.

[0062] In conjunction with the sixth aspect, in some implementations, before receiving the first frame from the first access point, the transceiver unit is further configured to: send a second frame to the first access point, the second frame being used to indicate parameters of the sequence carried by the second LTF.

[0063] In conjunction with the sixth aspect, in some implementations, both the first and second sequences are pseudo-random sequences.

[0064] In conjunction with the sixth aspect, in some implementations, before generating the second PPDU, the transceiver unit is further configured to: receive a first frame from the first access point, the first frame including second indication information, the second indication information being used to indicate that the sequence carried by the second LTF is a pseudo-random sequence.

[0065] In a seventh aspect, a communication device is provided. The device may be a first access point or a component of the first access point (e.g., a chip, circuit, or chip system). The device may have the functions described in the third aspect above. For example, the device includes a module, unit, or means corresponding to the operation involved in the third aspect above. The module, unit, or means may be implemented by software, hardware, or a combination of software and hardware.

[0066] Specifically, the device includes: a processing unit for generating a first PPDU, the first PPDU including a first LTF, the first LTF carrying a first sequence, the first sequence being used by a first site for channel estimation, the first LTF and the second LTF in the second PPDU not overlapping in the time domain, the first LTF and the second LTF in the second PPDU occupying the same frequency domain resources, the second LTF carrying a second sequence, the second sequence being used by a second site for channel estimation, and the second PPDU being a PPDU sent from a second access point to a second site; and a transceiver unit for sending the first PPDU to the first site.

[0067] Eighthly, a communication system is provided, which includes a first access point as described in the first aspect and a second access point as described in the second aspect, or includes a first access point and a second access point as described in the third aspect.

[0068] It should be understood that for any parts not described in detail in aspects four through eight, please refer to aspects one through three.

[0069] A ninth aspect provides a communication device comprising: a memory for storing a program; and at least one processor for executing the computer program or instructions stored in the memory to perform the method provided in any of the foregoing aspects or their implementations.

[0070] In one implementation, the device is either a first access point or a second access point.

[0071] In another implementation, the device is a chip, chip system, or circuit for use in a first access point or a second access point.

[0072] A tenth aspect provides a communication apparatus comprising: at least one processor and a communication interface, the at least one processor being configured to obtain a computer program or instructions stored in a memory via the communication interface to execute the method provided in any of the foregoing aspects or their implementations. The communication interface may be implemented in hardware or software.

[0073] In one implementation, the device also includes a memory.

[0074] Eleventhly, a processor is provided for executing the method provided in any of the preceding aspects.

[0075] Unless otherwise specified, or if it does not contradict its actual function or internal logic in the relevant description, the transmission and acquisition / reception operations involved in the processor can be understood as processor output and reception, input and other operations, or as transmission and reception operations performed by radio frequency circuits and antennas. This application does not limit them in this regard.

[0076] In a twelfth aspect, a computer-readable storage medium is provided that stores program code for execution by a device, the program code including methods for performing any of the above aspects or implementations thereof.

[0077] In a thirteenth aspect, a computer program product including instructions is provided, which, when run on a computer, causes the computer to perform the method provided in any of the above aspects or implementations thereof.

[0078] In a fourteenth aspect, a chip is provided, comprising a processor and a communication interface. The processor reads instructions stored in a memory through the communication interface and executes the methods provided in any of the above aspects or their implementations. The communication interface can be implemented in hardware or software.

[0079] Optionally, as one implementation, the chip also includes a memory storing computer programs or instructions, and a processor for executing the computer programs or instructions stored in the memory. When the computer programs or instructions are executed, the processor is used to perform the methods provided by any of the above aspects or their implementations.

[0080] When the method provided in this application is executed by a chip, this application does not limit the specific number of chips implementing the method. For example, it can be executed by one chip, or by two or more chips. Furthermore, when the number of chips implementing the method is two or more, the chip manufacturers are not limited; they can be from the same manufacturer or different manufacturers.

[0081] In a fifteenth aspect, a computer program is provided that, when run on a computer, causes the methods provided by any of the foregoing aspects or their implementations to be executed.

[0082] It should be understood that the beneficial effects of aspects two through fifteen and any of their implementations, as well as any aspects not described in detail, can be referred to aspect one and any of its implementations. Attached Figure Description

[0083] Figure 1 is a schematic diagram of a network architecture applicable to an embodiment of this application.

[0084] Figure 2 is a schematic diagram of the Co-SR transmission process.

[0085] Figure 3 is a schematic diagram of the Co-SR negotiation process.

[0086] Figure 4 is a schematic diagram of the EHT PPDU format.

[0087] Figure 5 is a schematic diagram of the UHR PPDU format.

[0088] Figure 6 is a schematic flowchart of a communication method 600 provided in this application.

[0089] Figure 7 is a schematic diagram of the construction of a multi-stream LTF sequence.

[0090] Figures 8 and 9 are schematic diagrams of the structure of the communication device provided in the embodiments of this application. Detailed Implementation

[0091] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0092] The embodiments of this application can be applied to wireless local area networks (WLANs), for example, supporting IEEE 802.11 related standards, such as 802.11a / b / g standards, 802.11n standards, 802.11ac standards, 802.11ax standards (i.e. Wi-Fi 6, also known as the high efficient (HE) standard), 802.11be standards (i.e. Wi-Fi 7, also known as the EHT) standards, 802.11bn standards (i.e. Wi-Fi 8, also known as the UHR standard) or next-generation standards of Wi-Fi 8, and also including 802.11ad, 802.11ay standards, etc. The embodiments of this application can also be applied to wireless local area network systems that support integrated millimeter wave (IMMW), wireless local area network systems that support ultra-wideband (UWB) such as the 802.15 series standards, sensing systems such as the 802.11bf series standards, or wireless positioning such as 802.11az. This application can also support standard protocols such as spark link and near link.

[0093] Although the embodiments of this application are primarily illustrated using the deployment of WLAN networks, particularly those employing the IEEE 802.11 system standard, those skilled in the art will readily understand that the various aspects involved in the embodiments of this application can be extended to other networks employing various standards or protocols, such as high-performance radio local area networks (HIPERLANs), wireless wide area networks (WWANs), wireless personal area networks (WPANs), or other networks now known or developed in the future. Therefore, regardless of the coverage area and wireless access protocol used, the various aspects provided in the embodiments of this application can be applied to any suitable wireless network.

[0094] The technical solutions of this application embodiment can also be applied to various communication systems, such as: WLAN communication systems, wireless fidelity (Wi-Fi) systems, 5th generation (5G) systems or new radio (NR) systems, future communication systems, Internet of Things (IoT) networks or vehicle-to-everything (V2X) networks, etc.

[0095] The communication systems described above are merely illustrative examples, and the communication systems applicable to this application are not limited to these. They will be uniformly described here and will not be repeated below.

[0096] Figure 1 is a schematic diagram of an application scenario applicable to an embodiment of this application. As shown in Figure 1, the method provided by this application is applicable to data communication between a station (STA) and an access point (AP). A station can also be referred to as a non-access point station (non-AP STA), or simply a non-AP station or station. Specifically, the solution of this application is applicable to communication between an AP and one or more non-AP stations (e.g., communication between AP1 and non-AP STA1, communication between AP2 and non-AP STA2), and also applicable to communication between APs (e.g., communication between AP1 and AP2).

[0097] It should be understood that in this application, AP can refer to an AP multi-link device (MLD) or an AP non-multi-link device, without limitation. Similarly, STA can refer to STA MLD or STA non-multi-link device, without limitation.

[0098] An Access Point (AP) can be a node that allows terminals (such as mobile phones) to access a wired (or wireless) network. It is primarily deployed in homes, buildings, and campuses, with a typical coverage radius of tens to hundreds of meters. Of course, it can also be deployed outdoors. An AP acts as a bridge connecting wired and wireless networks, its main function being to connect various wireless network clients together and then connect the wireless network to the Ethernet.

[0099] Specifically, an AP can be a terminal or network device with a Wi-Fi chip. This network device can be a server, router, switch, bridge, computer, mobile phone, relay station, vehicle-mounted equipment, wearable device, network device in a 5G network, network device in a future communication network, or network device in a public land mobile network (PLMN), etc. This application embodiment is not limited to these categories. The AP can be a device that supports Wi-Fi standards. For example, the AP can also support one or more standards in the IEEE 802.11 series, such as 802.11be, 802.11bn, and 802.11bn next generation.

[0100] Non-AP sites can be wireless communication chips, wireless sensors, or wireless communication terminals, and can also be referred to as users, user equipment (UE), access terminals, user units, user stations, mobile stations, mobile stations, remote stations, remote terminals, mobile devices, user terminals, terminals, wireless communication equipment, user agents, or user devices. Non-AP sites can be cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, IoT devices, wearable devices, terminal devices in 5G networks, terminal devices in future communication networks, or terminal devices in PLMNs, etc., and this application embodiment is not limited to these. Non-AP sites can be devices that support WLAN standards. For example, non-AP sites can support one or more standards in the IEEE 802.11 series, such as 802.11be, 802.11bn, and 802.11bn next generation.

[0101] For example, non-AP sites can be mobile phones, tablets, set-top boxes, smart TVs, smart wearable devices, vehicle communication devices, computers, Internet of Things (IoT) nodes, sensors, smart home devices such as smart cameras, smart remote controls, smart water and electricity meters, and sensors in smart cities.

[0102] The aforementioned AP or non-AP sites may include one or more of the following: transmitter, receiver, memory, processor, etc. The transmitter and receiver are used for transmitting and receiving packet structures, respectively; the memory is used to store signaling information and pre-agreed preset values, etc.; and the processor is used to parse signaling information and process related data, etc.

[0103] To facilitate understanding of the technical solutions of the embodiments of this application, some terms or concepts that may be involved in the embodiments of this application will be briefly described first.

[0104] 1. Multi-AP collaboration

[0105] With the development of wireless networks and the increasing prevalence of WLAN technology, WLAN devices are becoming increasingly dense. Because access points (APs) are easy to deploy, this increasing density also leads to more inter-cell interference. How to reduce inter-cell interference and improve user service quality through AP collaboration is a key issue that next-generation WLAN technology needs to address.

[0106] Specific mechanisms for multi-AP cooperation include coordinated orthogonal frequency division multiple access (co-OFDMA), coordinated time division multiple access (co-TDMA), Co-SR, Co-BF, and joint transmission.

[0107] 2. Co-SR transmission

[0108] Co-SR transmission refers to the simultaneous transmission of two access points (APs) on the same channel / resource block when they are far apart. By controlling power and user selection, interference between the two APs is minimized, thus effectively utilizing channel resources. Typically, the AP initiating multi-AP cooperative transmission is called the sharing AP or primary AP, and the other APs sharing transmission resources or opportunities are called shared APs or secondary APs. The sharing AP can control the transmission power of the shared APs, thereby controlling interference. Specifically, when a sharing AP obtains a TXOP and is about to send a downlink data frame to its associated site STA1, if the sharing AP finds that the channel conditions between it and STA1 are good enough to allow other APs to transmit concurrently (e.g., a shared AP sending data to its associated site STA2), it can select one or more shared APs for Co-SR transmission. When selecting shared APs, the sharing AP can preferentially choose APs farther from STA1, thereby reducing interference to STA1 when the shared APs are transmitting data. In addition, the shared AP can control the transmission power of the shared AP to further reduce the interference to STA1 when the shared AP transmits data.

[0109] A shared access point (AP) can initiate Co-SR transmission by sending a trigger frame to the shared AP. The shared AP will indicate several parameters for Co-SR transmission in the trigger frame, including the shared AP's transmit power, packet transmission duration, and the shared AP's transmit power. Upon receiving these parameters, the shared AP can prioritize data transmission with a station farther from the shared AP (such as STA2). Regarding the selection of transmission parameters for the shared AP, the interference experienced by STA2 due to the shared AP can be estimated based on the shared AP's transmit power, thereby selecting appropriate transmission parameters (such as modulation and coding scheme (MCS), number of spatial streams (NSS), or bandwidth) to ensure a high probability of successful data transmission for the shared AP.

[0110] In Co-SR transmission, interference may occur between two access points (APs) transmitting simultaneously on the same channel. For example, as shown in Figure 2, AP1 sends downlink data frames to STA1, while AP2 sends downlink data frames to STA2. STA1 receives the useful signal from AP1, but also receives the signal (interference) from AP2. When AP1 is a shared AP, if AP1 can predict the path loss between STA1 and AP2 before sending to STA1, it can control the transmission power of AP2, thus ensuring that the interference from AP2 to STA1 is low. When AP1 is a shared AP, if AP1 can predict the path loss between STA1 and AP2 before sending to STA1, it can choose appropriate transmission parameters to ensure successful transmission even if STA1 is affected by interference from AP2.

[0111] The Co-SR transmission process is explained below with reference to Figure 2.

[0112] Figure 2 is a schematic diagram of a Co-SR transmission process. As shown in Figure 2, AP1 (i.e., the sharing AP) can initiate Co-SR transmission by sending a Co-SR trigger frame to AP2 (i.e., the shared AP). Furthermore, AP1 and AP2 can perform Co-SR transmission according to the parameters in the Co-SR trigger frame. For example, AP1 can send downlink data frames to STA1, and AP2 can send downlink data frames to STA2.

[0113] It should be understood that Figure 2 shows a shared AP (e.g., AP2 shown in Figure 2), and in Co-SR transmission, multiple AP2s can participate in Co-SR transmission.

[0114] After STA1 and STA2 receive downlink data frames, they will respectively reply with acknowledgment information transmitted via Co-SR (e.g., an acknowledgment (ACK) frame or a block ACK (BA) frame). The acknowledgment information is used to indicate whether the STA has successfully received the downlink data frame. One method of replying with acknowledgment information is frequency division multiplexing, as shown in Figure 2, where STA1 and STA2 simultaneously reply with acknowledgment information on the frequency resources.

[0115] In addition, AP1 and AP2 can conduct a Co-SR negotiation process before Co-SR transmission to determine the parameters during the Co-SR transmission process.

[0116] Figure 3 illustrates the Co-SR negotiation process between AP1 and AP2. As shown in Figure 3, AP1 sends a Co-SR request frame to AP2, and AP2 sends a Co-SR response frame, completing the Co-SR negotiation process. This Co-SR negotiation process determines the sharing AP and the AP being shared with, as well as parameters such as transmit power, ensuring that each AP can efficiently and collaboratively perform spatial multiplexing. During the Co-SR negotiation process, the STA associated with AP1 and the STA associated with AP2 do not directly participate in the transmission and reception of Co-SR request and response frames, but they can listen in to obtain relevant information from the frames.

[0117] 3. Co-BF transmission

[0118] Co-BF transmission refers to the process where multiple APs with multiple antennas participating in Co-BF adjust the direction of signal transmission based on CSI (channel state information) to achieve better throughput and reliability, and reduce latency. Specifically, two APs participating in Co-BF (such as AP1 and AP2) can utilize the CSI between their own AP and another AP's non-AP STA (e.g., between AP1 and non-AP STA2, where non-AP STA2 is associated with AP2) to simultaneously transmit with their respective associated non-AP STAs while minimizing interference to other sites.

[0119] To determine the CSI between the AP and the non-AP STA, a Co-BF measurement (sounding) process is required before data transmission. The phase where the AP participating in Co-BF obtains the CSI through sounding can be called the Co-BF sounding phase, while the phase where data transmission is performed using Co-BF can be called the Co-BF transmission phase. The Co-BF transmission phase is largely similar to the Co-SR transmission phase shown in Figure 2, with the main difference being that the frames used in the Co-BF transmission phase can be referred to as Co-BF request frames, Co-BF response frames, and Co-BF trigger frames, respectively.

[0120] 4. PPDU in different formats

[0121] In the aforementioned multi-AP collaboration process, all frames (such as Co-SR request frames, Co-SR response frames, Co-SR trigger frames, Co-BF request frames, Co-BF response frames, Co-BF trigger frames, downlink data frames, ACK frames, and BA frames, etc.) belong to the Media Access Control (MAC) layer protocol data unit (MPDU), commonly referred to as a MAC frame. In actual communication, MAC frames are encapsulated into PPDUs before transmission. Different standards specify different PPDU formats; for example, the HE standard defines the HE PPDU, the EHT standard defines the EHT PPDU, and the UHR standard defines the UHR PPDU.

[0122] Figure 4 illustrates several formats of EHT PPDU, also known as 802.11be PPDU or PPDU in Wi-Fi 7. As shown in Figure 4, EHT PPDU includes two modes: Extremely High Throughput Multiple User PPDU (EHT MU PPDU) as shown in Figure 4(a) and Extremely High Throughput Trigger-Based PPDU (EHT TB PPDU) as shown in Figure 4(b). 802.11be uses EHT MU PPDU to transmit data simultaneously to both single-user and multi-user devices, reducing the number of PPDU formats that the device needs to support and simplifying implementation complexity. EHT TB PPDU is a trigger-based format, meaning that after multiple stations receive a trigger frame, they simultaneously perform uplink multi-user transmission based on the resource scheduling information in the trigger frame. The EHT MU PPDU includes the legacy short training field (L-STF), legacy long training field (L-LTF), legacy signal field (L-SIG), legacy signal repeat field (RL-SIG), universal signal field (U-SIG), EHT signal field (EHT-SIG), EHT short training field (EHT-STF), EHT long training field (EHT-LTF), data field, and packet extension (PE) field. The EHT TB PPDU includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-STF, EHT-LTF, data field, and PE field.

[0123] Figure 5 is a schematic diagram of the UHR PPDU format. UHR PPDU can also be called 802.11bn PPDU or PPDU in Wi-Fi 8. As shown in Figure 5, UHR PPDU includes the Ultra High Reliability Multiple User PPDU (UHR MU PPDU) shown in Figure 5(a) and the Ultra High Reliability Trigger-Based PPDU (UHR TB PPDU) shown in Figure 5(b). As shown in Figure 5(a), the UHR MU PPDU includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR signal field (UHR-STG), UHR short training field (UHR-STF), UHR long training field (UHR-LTF), data field, and PE field. As shown in Figure 5(b), the UHR TB PPDU includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR UHR-STF, UHR-LTF, the data field, and the PE field. In addition, the UHR PPDU also includes the UHR Co-SR PPDU, which is a variant of the UHR MU PPDU.

[0124] 5. LTF sequence

[0125] LTF sequences can be used for channel estimation, and different bandwidths correspond to different LTF sequences. The standard defines several different LTF sequences. Based on these sequences, the transmitter can generate the LTF sequence to be transmitted, i.e., the LFT sequence carried in the LTF of the PPDU. For ease of distinction, this application refers to the LTF sequence defined in the standard as the base sequence, and the LFT sequence carried in the LTF of the PPDU as simply the LTF sequence. Therefore, unless otherwise specified, the LTF sequence refers to the LFT sequence carried in the LTF of the PPDU, or the processed LTF sequence, or the LTF sequence to be transmitted. For example, the EHT MU PPDU and EHT TB PPDU shown in Figure 4 both include EHT-LTF, and the UHR MU PPDU and UHR TB PPDU shown in Figure 5 both include UHR-LTF. Both EHT-LTF and UHR-LTF can carry LTF sequences for channel estimation at the receiver.

[0126] Taking the communication architecture shown in Figure 2 as an example, assume that the downlink data frame sent by AP1 to non-AP STA 1 is encapsulated in PPDU 1, and the downlink data frame sent by AP2 to non-AP STA 2 is encapsulated in PPDU 2. Further assume that both PPDU 1 and PPDU 2 are UHR MU PPDUs. Then, both PPDU 1 and PPDU 2 include UHR-LTF. The UHR-LTF in PPDU 1 is used by non-AP STA 1 for channel estimation, so that non-AP STA 1 can correctly parse the downlink data frame in PPDU 1. The UHR-LTF in PPDU 2 is used by non-AP STA 2 for channel estimation, so that non-AP STA 2 can correctly parse the downlink data frame in PPDU 2.

[0127] As can be seen from the above, in the process of multi-AP cooperation, each AP sends an LTF sequence for its respective receiver to perform channel estimation. However, there may be interference between the LTF sequences sent by different APs, which will affect the accuracy of STA channel estimation.

[0128] For example, taking AP1 and STA1 in Figure 2 as examples, the target receiver of the downlink data transmitted by AP1 is STA1, and the channel through which the downlink data traverses is h. STA1,AP1 However, STA1 receives not only the LTF sequence from AP1 (i.e., the sequence carried by UHR-LTF in PPDU 1), but also the LTF sequence from AP2 (i.e., the sequence carried by UHR-LTF in PPDU 1). Therefore, the channel estimated by STA1 is... Where h STA1,AP1 Indicates the channel between AP1 and STA1, h STA1,AP2 This indicates the channel between AP2 and STA1.

[0129] In view of this, this application proposes a communication method and communication device that can reduce mutual interference when multiple APs cooperate and improve the accuracy of channel estimation.

[0130] It should be understood that the embodiments shown below use a first access point, a second access point, a first site, a second site, etc., as examples to illustrate the method. However, this application does not limit the execution subject; any program that can run the code of the method provided in the embodiments of this application can communicate according to the method provided in the embodiments of this application. The execution subject of the method provided in the embodiments of this application can be a first access point, a second access point, a first site, a second site, etc., or a functional module among the first access point, second access point, first site, second site, etc., that can call and execute the program, and there is no limitation.

[0131] Figure 6 is a schematic flowchart of a communication method 600 provided in this application. As shown in Figure 6, the method 600 includes the following steps.

[0132] S610, the first access point generates the first PPDU.

[0133] In this application, the first access point can be referred to as the sharing AP or the master AP, which is the initiator of multi-AP collaboration, and the second access point can be referred to as the shared AP or the slave AP, which is the responder of multi-AP collaboration. Specifically, the mechanism of multi-AP collaboration can be Co-SR, Co-BF, etc.

[0134] The first PPDU includes a first LTF, which is used to carry a first sequence. The first sequence is used by the first site for channel estimation. Alternatively, the first LTF can be said to be used by the first site for channel estimation.

[0135] For example, the first PPDU is an EHT PPDU (as shown in Figure 4), which can be an EHT MU PPDU, an EHT TB PPDU, or any other form of EHT PPDU besides those shown in Figure 4, without limitation. When the first PPDU is an EHT PPDU, the first LTF can be an EHT LTF, and the first sequence can be an EHT LTF sequence. The first PPDU can also be a UHR PPDU (as shown in Figure 5), which can be a UHR MU PPDU, a UHR TB PPDU, or any other form of UHR PPDU besides those shown in Figure 5, without limitation. When the first PPDU is a UHR PPDU, the first LTF can be a UHR LTF, and the first sequence can be a UHR LTF sequence. Regardless of the type of the first sequence, it can be used by the receiver for channel estimation. Since the receiver of the first PPDU is the first site, the first sequence is used by the first site for channel estimation.

[0136] It should be understood that the first sequence refers to the sequence to be sent by the first access point, rather than the base sequence defined by the protocol. The first sequence can be generated based on the base sequence, which will be explained in detail later.

[0137] S620, the second access point generates the second PPDU.

[0138] Similarly, the second PPDU includes a second LTF, which is used to carry a second sequence, and the second sequence is used for channel estimation at the second site. Alternatively, it can be said that the second LTF is used for channel estimation at the second site.

[0139] For example, the second PPDU is an EHT PPDU (as shown in Figure 4), which can be an EHT MU PPDU or an EHT TB PPDU, without limitation. When the second PPDU is an EHT PPDU, the second LTF can be an EHT LTF, and the second sequence can be an EHT LTF sequence. The second PPDU can also be a UHR PPDU (as shown in Figure 5), which can be a UHR MU PPDU or a UHR TB PPDU, without limitation. When the second PPDU is a UHR PPDU, the second LTF can be a UHR LTF, and the second sequence can be a UHR LTF sequence. Regardless of the type of the second sequence, it can be used for channel estimation at the receiver. Since the receiver of the second PPDU is the second site, the second sequence is used for channel estimation at the second site.

[0140] Similarly, the second sequence refers to the sequence to be sent by the second access point, rather than the base sequence defined by the protocol. The second sequence can be generated based on the base sequence, as will be explained later.

[0141] In this configuration, the first LTF and the second LTF occupy the same time-frequency resources, or in other words, the first PPDU and the second PPDU occupy the same time-frequency resources. Alternatively, the first PPDU and the second PPDU occupy the same time-domain resources, or in other words, the first PPDU and the second PPDU occupy the same frequency-domain resources.

[0142] Specifically, the first access point and the second access point are APs that cooperate in multiple APs. Since the data PPDUs transmitted by different APs need to be aligned during the multi-AP cooperation process (i.e., start and end at the same time), the first PPDU and the second PPDU occupy the same time and frequency resources. At this time, the first LTF and the second LTF can also be aligned in the frequency domain and the time domain.

[0143] It should be understood that the relationship between the time-frequency resources of the first PPDU and the second PPDU mainly depends on the protocol's provisions regarding the multi-AP cooperation mechanism. This application uses the example of the first LTF and the second LTF occupying the same time-frequency resources for illustration.

[0144] For example, the first LTF and the second LTF occupying the same time-frequency resources can mean that: the GI of the symbols occupied by the first LTF and the GI of the symbols occupied by the second LTF are the same; the number of symbols occupied by the first LTF and the number of symbols occupied by the second LTF are the same; the number of subcarriers occupied by the first LTF and the number of subcarriers occupied by the second LTF are the same; and the subcarrier spacing of the subcarriers occupied by the first LTF and the subcarrier spacing of the subcarriers occupied by the second LTF are the same.

[0145] It should be understood that since the first LTF is used to carry the first sequence, "symbols occupied by the first LTF" can also be understood as symbols carrying the first sequence, and "subcarriers occupied by the first LTF" can also be understood as subcarriers carrying the first sequence. Similarly, since the second LTF is used to carry the second sequence, "symbols occupied by the second LTF" can also be understood as symbols carrying the second sequence, and "subcarriers occupied by the second LTF" can also be understood as subcarriers carrying the second sequence.

[0146] In this application, the symbols occupied by a field refer to all symbols required from the start of transmission of that field to the end of transmission; these are the time-domain resources occupied by that field. Generally, these symbols refer to orthogonal frequency division multiple (OFDM) symbols. The subcarriers occupied by a field refer to all subcarriers required from the start of transmission of that field to the end of transmission; these are the frequency-domain resources occupied by that field. The subcarriers occupied by a field can also be described as the subcarriers corresponding to the symbols occupied by the field.

[0147] Furthermore, in this application, the sequence used for channel estimation is an LTF sequence. Therefore, the number of symbols occupied by the first LTF can also be called the number of LTF symbols of the first PPDU, and the number of symbols occupied by the second LTF can also be called the number of LTF symbols of the second PPDU.

[0148] It should be understood that GI is a gap in time inserted between OFDM symbols, carrying no information, and is used to eliminate symbol establishment interference caused by multipath propagation. By inserting GI, it can be ensured that the multipath delay of one symbol does not affect the current symbol. For example, GI can be one of several values ​​such as 0.8µs, 1.6µs, 3.2µs, etc.

[0149] In this application, the GI of the symbol can also be replaced with the cyclic prefix (CP) of the symbol, that is, as long as the format of the frequency domain resources occupied by the first LTF is the same as that of the second LTF.

[0150] Furthermore, the subcarrier spacing and the number of subcarriers occupied by the first LTF can be determined based on the mode of the first LTF. Therefore, the mode of the first LTF is the same as that of the second LTF. Specifically, LTF sequence modes include 1xLTF, 2xLTF, 4xLTF, etc. Among them, 1xLTF means that only one of the four adjacent subcarriers is used for data transmission, 2xLTF means that only one of the two adjacent subcarriers is used for transmission, and 4xLTF means that every subcarrier is used for transmission. For example, assuming that the first PPDU occupies 20MHz and the mode is 4x, the number of Fast Fourier Transform (FFT) points is 64*4=256, that is, the total number of subcarriers is 256, and the corresponding subcarrier spacing is 20MHz / 256=78.125kHz.

[0151] The first sequence and the second sequence are different; that is, the first sequence and the second sequence are two different sequences.

[0152] It should be understood that the difference between the first sequence and the second sequence can mean that the first sequence and the second sequence are independent and unrelated, or that the first sequence and the second sequence are related but still different sequences. Specifically, their content is different, and their types can be the same or different, without restriction. For example, the first sequence and the second sequence are both EHT LTF sequences, or the first sequence and the second sequence are both UHR LTF sequences, or the first sequence is an EHT LTF sequence and the second sequence is a UHR LTF sequence, or the first sequence is a UHR LTF sequence and the second sequence is an EHT LTF sequence.

[0153] For example, the first sequence can be determined by the first access point itself. For instance, the first access point generates the first sequence based on the base sequence and P matrix predefined by the protocol. Or, if the protocol predefined the first sequence as a pseudo-random sequence, the first access point can generate a pseudo-random sequence as the first sequence.

[0154] As one implementation, the first access point is generated based on the predefined base sequence and P matrix of the protocol.

[0155] In multi-stream scenarios, in order to accurately estimate spatial stream channels, the WIFI standard proposes to maintain the orthogonality of LTF sequences on each spatial stream by multiplying the P matrix by the base sequence on the data subcarrier.

[0156] Taking a spatial flow of 2 as an example, the corresponding P matrix is:

[0157] Taking a spatial flow of 4 as an example, the corresponding P matrix is:

[0158] Taking a spatial flow of 6 as an example, the corresponding P matrix is:

[0159] Figure 7 is a schematic diagram of the construction of a multi-stream LTF sequence. As shown in Figure 7, the labeled times are the cyclic shift delay (CSD) corresponding to each spatial stream. For the case where the number of spatial streams is less than 4, the corresponding LTF sequence can be seen in the dashed box in Figure 7. The k-th element of the LTF sequence is carried on the k-th subcarrier. k Furthermore, the LTF of the nth OFDM symbol corresponding to the mth spatial stream is multiplied by the element in the mth row and nth column of the P matrix. Therefore, for the data passing through channel H... k Subsequently, the frequency domain signal Y received by the non-AP STA k It can be represented as: Y k =H k P 4*4 LTF k Since matrix P is an orthogonal matrix (e.g., I is the identity matrix, and * is the conjugate transpose of the matrix. Therefore, the channel on the k-th subcarrier... In this way, the multiple input multiple output (MIMO) channel corresponding to the k-th subcarrier can be estimated.

[0160] It should be understood that there are currently three types of subcarriers: data subcarriers, pilot subcarriers, and unused subcarriers. Data subcarriers are used for actual data transmission; pilot subcarriers are used to provide phase information and parameter tracking; unused subcarriers are neither data subcarriers nor pilot subcarriers, and include the central direct current (DC) subcarrier, guard band, and empty subcarriers. The frequency domain resources for transmitting PPDUs are generally resource units (RUs), and one RU includes data subcarriers and pilot subcarriers. The LTF construction method described above only applies to data subcarriers. For pilot subcarriers, the corresponding LTF construction method is similar to that of data subcarriers, but the difference is that the LTF construction method of pilot subcarriers uses an R matrix instead of a P matrix. The relationship between the R matrix and the P matrix is: R(m,n) = P(1,n), that is, each row of the R matrix is ​​equal to the first row of the P matrix. For details on the P matrix and R matrix, please refer to the 802.11 series of standards, which will not be elaborated here.

[0161] Therefore, the first access point can select the corresponding P matrix based on the number of spatial streams transmitted by the first access point and the second access point, select one row from it as a coefficient, and multiply the coefficient by the base sequence to obtain the first sequence.

[0162] Spatial streams, also known as space-time streams, operate based on MIMO and beamforming technologies. MIMO allows devices to simultaneously transmit multiple data streams using multiple antennas, while beamforming dynamically adjusts the signal direction to concentrate the wireless signal onto a specific receiving device, thereby improving signal strength and stability. The number of spatial streams refers to the number of independent data streams transmitted and received simultaneously through multiple antennas on the same spectrum. The number of spatial streams determines the number of data channels that can be transmitted in parallel within the same timeframe, thus affecting network transmission speed and capacity. Different WiFi standards support different maximum numbers of spatial streams: WiFi 4 (802.11n) supports a maximum of 4 spatial streams, WiFi 5 (802.11ac) supports a maximum of 8 spatial streams, and WiFi 6 (802.11ax) supports a maximum of 8 spatial streams, offering improved efficiency and performance compared to WiFi 5. WiFi 7 (802.11be) theoretically supports 16 spatial streams, but in practice, this is limited by hardware.

[0163] In this application, the first access point and the second access point cooperate in multiple APs. Therefore, the number of spatial streams transmitted by the first access point and the second access point is the sum of the number of spatial streams corresponding to the first PPDU and the number of spatial streams corresponding to the second PPDU.

[0164] It should be understood that the number of spatial streams corresponding to a PPDU refers to the number of spatial streams a device needs to use when transmitting that PPDU. Depending on the device's hardware architecture and other parameters, the maximum number of spatial streams supported by each device is fixed. However, when transmitting each PPDU, the device can choose the number of spatial streams corresponding to that PPDU, as long as the number of spatial streams corresponding to the PPDU is less than or equal to the number of spatial streams supported by the device. Therefore, in this context, the maximum number of spatial streams supported by the first access point is greater than or equal to the number of spatial streams corresponding to the first PPDU; similarly, the maximum number of spatial streams supported by the second access point is greater than or equal to the number of spatial streams corresponding to the second PPDU.

[0165] Furthermore, the number of symbols occupied by the first LTF is determined based on the number of spatial streams transmitted by the first access point and the second access point. For example, the number of symbols occupied by the first LTF is greater than or equal to the sum of the number of spatial streams corresponding to the first PPDU and the second PPDU. Similarly, the number of symbols occupied by the second LTF is also greater than or equal to the sum of the number of spatial streams corresponding to the first PPDU and the second PPDU.

[0166] Specifically, the horizontal axis in Figure 7 represents time, i.e., symbols. Each data stream corresponds to one symbol. In other words, the dimension of the P matrix is ​​the total number of symbols, which is also the total number of transmittable spatial streams. To ensure that the number of spatial streams required by the first access point and the second access point can both be transmitted, the number of symbols occupied by the first LTF should be greater than or equal to the sum of the number of spatial streams corresponding to the first PPDU and the second PPDU. For example, the LTF symbol count of AP1 (an example of the first access point) (i.e., the number of symbols occupied by the first LTF) and the LTF symbol count of AP2 (an example of the second access point) (i.e., the number of symbols occupied by the second LTF) are both 4. Thus, the dimension of the P matrix is ​​4*4, which is the aforementioned P... 4*4 There are 4 available sequences (i.e., the number of rows in matrix P). AP1 can use sequence 1 (i.e., the sequence obtained with the first row of matrix P as the coefficient) and sequence 2 (i.e., the sequence obtained with the second row of matrix P as the coefficient). AP2 can use sequence 3 (i.e., the sequence obtained with the third row of matrix P as the coefficient) and sequence 4 (i.e., the sequence obtained with the fourth row of matrix P as the coefficient).

[0167] In this implementation, the second sequence is orthogonal to the first sequence. In other words, the first and second sequences are related, but they are still different sequences.

[0168] Similarly, for the second access point, it can also select a row from the P matrix that is different from the first access point as its coefficient, and multiply this coefficient by the base sequence to obtain the second sequence. Since the P matrix is ​​an orthogonal matrix, the first and second sequences are orthogonal.

[0169] For example, the spatial flow number corresponding to the first PPDU and the spatial flow number corresponding to the second PPDU are both 1, and the P matrix is ​​as described above. 2*2 If the matrix is ​​used, the first access point can choose the first row as the coefficients for generating the first sequence, and the second access point can choose the second row as the coefficients for generating the second sequence.

[0170] Since the inner product between two orthogonal sequences is zero or a negative multiple of the sequence length, interference between different sequences can cancel each other out. In this application, the first sequence used for channel estimation at the first site and the second sequence used for channel estimation at the second site are orthogonal. Therefore, mutual interference when two access points cooperate can be reduced, and the accuracy of channel estimation can be improved.

[0171] Optionally, in this implementation, before S610 and S620, the method 600 further includes: S601a, whereby the first access point sends a first frame to the second access point, and correspondingly, the second access point receives the first frame.

[0172] The first frame includes first indication information, which indicates that the sequence carried by the second LTF is orthogonal to the first sequence. For example, the sequence orthogonal to the first sequence includes the second sequence.

[0173] Specifically, the first indication information can directly indicate the parameters of the second sequence, such as: the guard interval of the symbols carrying the second sequence, the number of subcarriers corresponding to the symbols carrying the second sequence, the number of symbols carrying the second sequence, the subcarrier spacing of the subcarriers corresponding to the symbols carrying the second sequence, and the starting row index of the coefficients used to generate the second sequence in the P matrix (i.e., which row in the P matrix can be used as a candidate coefficient to generate the second sequence). Alternatively, the first indication information can also indicate the parameters of the first sequence, such as: the guard interval of the symbols carrying the first sequence, the number of subcarriers corresponding to the symbols carrying the first sequence, the number of symbols carrying the first sequence, the subcarrier spacing of the subcarriers corresponding to the symbols carrying the first sequence, and the row index of the coefficients used to generate the first sequence in the P matrix (i.e., which row in the P matrix the first sequence is generated from). In this way, the second access point can use the same guard interval, number of subcarriers, number of symbols, and subcarrier spacing as the first LTF to carry the second sequence, and select other rows in the P matrix (i.e., rows different from those used to generate the first sequence) to generate the second sequence. Alternatively, the first indication information may only indicate the starting row index of the coefficients used to generate the second sequence in the P matrix, while the symbol GI, number of subcarriers, number of symbols, subcarrier spacing, etc., can be indicated by other signaling in the multi-AP cooperation mechanism, thus reducing the indication overhead.

[0174] Optionally, the row index of the coefficients used to generate the first sequence in the P matrix can also be replaced with the spatial stream number corresponding to the first PPDU. For example, the protocol defaults to the first and second access points selecting rows in the P matrix in a top-down order. Therefore, when the spatial stream number corresponding to the first PPDU is 1, it means that the first matrix selects the first row of the P matrix as the coefficients for generating the first sequence. When the spatial stream number corresponding to the first PPDU is 2, it means that the first matrix selects the first and second rows of the P matrix as the coefficients for generating the first sequence. When the spatial stream number corresponding to the first PPDU is 3, it means that the first matrix selects rows 1 to 3 of the P matrix as the coefficients for generating the first sequence. Other cases follow the same logic and will not be elaborated here.

[0175] Optionally, the starting row index of the coefficients used to generate the second sequence in the P matrix can be replaced with the spatial stream number corresponding to the first PPDU. For example, if the protocol defaults to the first and second access points selecting rows in the P matrix in a top-down order, then when the spatial stream number corresponding to the first PPDU is 1, it means that the first matrix selects the first row of the P matrix as the coefficients for generating the first sequence. In this case, the starting row index of the coefficients used to generate the second sequence in the P matrix is ​​the second row, indicating that the second access point can start selecting from the second row. When the spatial stream number corresponding to the first PPDU is 2, it means that the first matrix selects the first and second rows of the P matrix as the coefficients for generating the first sequence. In this case, the starting row index of the coefficients used to generate the second sequence in the P matrix is ​​the third row, indicating that the second access point can start selecting from the third row. When the spatial stream number corresponding to the first PPDU is 3, it means that the first matrix selects rows 1 to 3 in the P matrix as the coefficients for generating the first sequence. In this case, the starting row index of the coefficients used to generate the second sequence in the P matrix is ​​row 4, indicating that the second access point can be selected starting from row 4. Other cases follow the same logic and will not be elaborated here.

[0176] In this application, "row index" can be understood as the i-th row (i is a positive integer), or the position of the row.

[0177] It should be understood that in this application, the first sequence can be one or more, without limitation. The number of first sequences can be the same as the number of spatial streams corresponding to the first PPDU, that is, each first sequence corresponds to one spatial stream of the first PPDU. Similarly, the second sequence can be one or more, without limitation. The number of second sequences can be the same as the number of spatial streams corresponding to the second PPDU, that is, each second sequence corresponds to one spatial stream of the second PPDU. Furthermore, when the first sequence and / or the second sequence are multiple sequences, each first sequence and each second sequence are orthogonal to each other, and any two first sequences are also orthogonal to each other, and any two second sequences are also orthogonal to each other. For example, in the example above, when AP1 uses sequence 1 and sequence 2, and AP2 uses sequence 3 and sequence 4, sequence 1 and sequence 2 can both be regarded as examples of the first sequence, and sequence 3 and sequence 4 can both be regarded as examples of the second sequence, and since sequence 1 to sequence 4 are respectively based on P 4*4 The sequences are generated from rows 1 to 4 of the matrix, therefore any two sequences from sequence 1 to sequence 4 are orthogonal.

[0178] As an example, the first frame is used to initiate the negotiation process of the multi-AP collaboration process. For example, the first frame is used to initiate the Co-SR negotiation process, which is a Co-SR request frame; or the first frame is used to initiate the Co-BF negotiation process, which is a Co-BF request frame.

[0179] As another example, the first frame is used to initiate the transmission process of a multi-AP cooperative process. For example, the first frame is used to initiate the Co-SR transmission process, and it is the Co-SR trigger frame; or the first frame is used to initiate the Co-BF transmission process, and it is the Co-BF trigger frame.

[0180] Optionally, in this implementation, the first indication information may also indicate the spatial stream number corresponding to the second PPDU.

[0181] Specifically, the first access point is a sharing AP, which can indicate the number of spatial streams corresponding to the second PPDU. For example, in the example above, when AP1 uses sequence 1 and sequence 2 and the dimension of the P matrix is ​​4*4, AP1 can indicate that the number of spatial streams corresponding to the second PPDU transmitted by AP2 is 2 or 1. This can avoid mutual interference caused by AP2 using 3 or more streams to transmit the second PPDU.

[0182] It should be understood that the first access point may not indicate the number of spatial streams corresponding to the second PPDU, and the second access point may make its own decision. For example, when AP1 uses sequence 1 and the dimension of the P matrix is ​​4*4, AP2 may use at least one of the sequences from sequence 2 to sequence 4. In this case, AP1 may not indicate the number of spatial streams corresponding to the second PPDU transmitted by AP2, and AP2 may make its own decision. This provides AP2 with greater freedom and flexibility.

[0183] Optionally, in this implementation, the first frame may also include fourth indication information, which is used to indicate that the second access point does not need to perform the interference zeroing precoding strategy.

[0184] Specifically, Co-BF transmission utilizes multiple transmitting antennas working together to form a directional beam, enhancing signal transmission in a specific direction. However, in real-world environments, various interference sources exist, such as signals from other wireless communication devices and environmental noise, which can affect the performance of Co-BF transmission. Interference nulling technology, through a series of algorithms and processing methods, can identify and suppress these interfering signals. It is typically based on adaptive array technology of digital beamforming, adjusting the weighting coefficients of the antenna array to nullify or maximally weaken interfering signals at the receiver. This allows the receiver to more accurately receive the useful signal transmitted by the transmitter, thereby improving transmission reliability and efficiency. In this implementation, since the first and second sequences are orthogonal, interference cancellation can be achieved; that is, interference nulling is unnecessary, as the orthogonal sequences can eliminate interference. Therefore, in Co-BF transmission scenarios, the first access point can instruct the second access point not to perform interference nulling during precoding, thus reducing the implementation complexity of the second access point.

[0185] For example, the fourth indication information can be 1 bit. For instance, a value of 0 indicates that the second access point does not need to perform the interference zeroing precoding strategy, and a value of 1 indicates that the second access point needs to perform the interference zeroing precoding strategy.

[0186] Optionally, in this implementation, before S601a, the method 600 further includes: S602, whereby the second access point sends a second frame to the first access point, and correspondingly, the first access point receives the second frame.

[0187] The second frame is used to indicate the parameters of the sequence carried by the second LTF. Specifically, the second frame may indicate the parameters of the sequence that the second access point needs to use, such as minimum requirements.

[0188] For example, the parameters of the sequence carried by the second LTF required by the second access point may include at least one of the following: the guard interval of the symbols carrying the second sequence, the number of subcarriers corresponding to the symbols carrying the second sequence, the number of symbols carrying the second sequence, the subcarrier spacing of the subcarriers corresponding to the symbols carrying the second sequence, the number of spatial streams corresponding to the second PPDU, etc.

[0189] The second frame can be used to determine the first indication information. In other words, the first access point can determine the first indication information based on the parameters required by the second access point. For example, the parameters of the second sequence indicated by the first access point cannot be lower than the minimum requirements of the second access point. Or, some of the parameters of the second sequence indicated by the first access point meet the minimum requirements of the second access point, while some do not.

[0190] For example, if AP2 indicates that it needs to use two spatial streams to transmit the second PPDU, then when AP1 transmits only one spatial stream, the total number of spatial streams is 3. Therefore, AP1 can indicate a total LTF symbol count of 4. Similarly, if AP2 indicates that it needs to use one spatial stream to transmit the second PPDU, then when AP1 transmits only one spatial stream, the total number of spatial streams is 2. AP1 can also indicate a total LTF symbol count of 2.

[0191] Optionally, the second frame may include third indication information, which is used to indicate whether the second access point requests the number of spatial streams corresponding to the second PPDU, or whether the first access point needs to indicate the number of spatial streams corresponding to the second PPDU to the second access point, or whether the second access point needs to determine the number of spatial streams corresponding to the second PPDU itself.

[0192] Specifically, the second access point can indicate to the first access point whether it needs to determine the number of spatial flows corresponding to the second PPDU itself. If the second access point needs to determine it itself, it means that the second access point does not need to request the number of spatial flows corresponding to the second PPDU, and the first access point also does not need to indicate the number of spatial flows corresponding to the second PPDU to the second access point. In this case, the first access point does not need to indicate the number of spatial flows corresponding to the second PPDU. Conversely, if the second access point does not need to determine it itself, it means that the second access point needs to request the number of spatial flows corresponding to the second PPDU, and the first access point also needs to indicate the number of spatial flows corresponding to the second PPDU to the second access point. In this case, the first access point can indicate the number of spatial flows corresponding to the second PPDU to the second PPDU.

[0193] For example, when the second access point determines the number of spatial streams corresponding to the second PPDU, it can determine the number of spatial streams corresponding to the second PPDU based on its own hardware conditions and transmission requirements of the second PPDU. This application does not limit the specific method by which the second access point determines the number of spatial streams corresponding to the second PPDU.

[0194] As an example, the second frame is used to respond to the negotiation process of the multi-AP collaboration process. For example, the second frame is used to respond to the Co-SR negotiation process, and it is a Co-SR response frame; similarly, the first frame is used to respond to the Co-BF negotiation process, and it is a Co-BF response frame.

[0195] As another implementation method, the first access point can generate a pseudo-random sequence as the first sequence.

[0196] In this implementation, the second sequence can also be a pseudo-random sequence. This reduces the probability that the first and second access points use the same LTF sequence, thus reducing interference between the two access points.

[0197] For example, both the first and second sequences are randomized secure LTF sequences used for secure ranging in the 802.11az standard. Alternatively, both the first and second sequences are pseudo-random 64-phase quadrature amplitude modulation (QAM) sequences in the 802.11ad standard.

[0198] In this implementation, both the first sequence and the second sequence are pseudo-random sequences. They can be regarded as two independent and unrelated sequences, with the first access point and the second access point generating their own required sequences.

[0199] For example, a first access point can generate a first sequence based on its first BSS color, and a second access point can generate a second sequence based on its second BSS color. The first BSS color identifies the BSS to which the first access point belongs, and the second BSS color identifies the BSS to which the first access point belongs. Alternatively, the first access point can generate a first sequence based on its own identifier (such as MAC address, service set identifier (SSID), etc.), and the second access point can generate a second sequence based on its own identifier (such as MAC address, service set identifier (SSID), etc.). Since the BSS and identifiers of the first and second access points are different, this ensures that the generated first and second sequences are also different, thereby reducing interference.

[0200] It should be understood that a BSS can include an AP and one or more non-AP sites associated with that AP. For example, in Figure 1, AP1 belongs to one BSS and AP2 belongs to another BSS. The BSS color is used to uniquely identify a BSS. Therefore, the BSS color of the BSS to which AP1 belongs is different from the BSS to which AP2 belongs.

[0201] For example, assuming that both the first and second PPDUs occupy 20MHz and the mode is 2x, then the first and second PPDUs collectively use the following portions of subcarriers numbered -122 to 122: {–122,–120,–118,–116,–114,–112,–110,–108,–106,–104,–102,–100,–98,–96,–94,–92,–90,–88,–86,–84,–82,–80,–78,–76,–74,–72,–70,–68,–66,–64,–62,–60,–58,–56,–54,–52,–50,–48,–46,–44,–42,–40,–38} –36,–34,–32,–30,–28,–26,–24,–22,–20,–18,–16,–14,–12,–10,–8,–6,–4,–2,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44 The sequence of numbers is: 46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78,80,82,84,86,88,90,92,94,96,98,100,102,104,106,108,110,112,114,116,118,120,122. For the first subcarrier, the first and second access points can use 7 + (n-1)*122 pseudo-random octal numbers (i.e., 64-QAM). For the k-th subcarrier, the first and second access points can use 6 + k + (n-1)*122 pseudo-random octal numbers. Wherein, for the first access point, n is the BSS color + symbol number of the first access point, and for the second access point, n is the BSS color + symbol number of the second access point.

[0202] Optionally, in this implementation, before S610 and S620, the method 600 further includes: S601b, whereby the first access point sends a first frame to the second access point, and correspondingly, the second access point receives the first frame.

[0203] The first frame includes second indication information, which is used to indicate that the sequence carried by the second LTF is a pseudo-random sequence.

[0204] Specifically, the protocol may predefine the use of a pseudo-random sequence, or the first access point and the second access point may negotiate the use of a pseudo-random sequence. As a specific negotiation process, the first access point may indicate to the second access point, through a second indication message, that a random sequence, namely the LTF sequence, should be used.

[0205] For example, the second indication information can be 1 bit, for instance, a value of 0 to indicate that the second access point does not use a pseudo-random sequence, and a value of 1 to indicate that the second access point uses a pseudo-random sequence.

[0206] S630, the first access point sends a first PPDU to the first site, and the first site receives the first PPDU accordingly.

[0207] The first PPDU received by the first station is the first PPDU that has passed through the wireless channel. For example, the first sequence received by the first station is the first sequence that has passed through the wireless channel.

[0208] It should be understood that there can be one or more first sites associated with the first access point, without limitation. Similarly, there can also be one or more second sites associated with the second access point, and the number of second sites can be the same as or different from the number of first sites, without limitation.

[0209] Furthermore, this application does not impose any restrictions on the transmission method of PPDU. For details, please refer to the description of the PPDU transmission method between AP and STA specified in existing or future protocols, which will not be elaborated here.

[0210] S640, the second access point sends a second PPDU to the second station, and the second station receives the second PPDU accordingly.

[0211] The second PPDU received by the second station is a second PPDU that has passed through the wireless channel. For example, the second sequence received by the second station is a second sequence that has passed through the wireless channel.

[0212] Furthermore, in method 600, there can be one first access point, and there can be multiple second access points or only one; there is no restriction. When there are multiple second access points, each second access point can execute the steps of S640.

[0213] In addition, when there are multiple second access points, there can be multiple second frames. The second frames of different access points can be transmitted in a trigger-based manner, such as through uplink orthogonal frequency division multiple access (UL OFDMA) or uplink multi-user multiple-input and multiple-output (UL MU-MIMO) transmission mode, or in a time-division manner.

[0214] Optionally, the method 600 further includes: S650, the first station performs channel estimation based on a first sequence passing through the wireless channel and a preset first sequence.

[0215] It should be understood that the preset first sequence is the same as the first sequence in steps S610 and S620. After receiving and parsing the PPDU, the receiving end obtains the first sequence that has passed through the wireless channel and compares it with the preset first sequence to complete the channel estimation. The specific implementation method of channel estimation can refer to existing schemes and will not be described here.

[0216] Optionally, the method 600 further includes: S660, the second station performs channel estimation based on a second sequence passing through the wireless channel and a preset second sequence.

[0217] It should be understood that the preset second sequence is the second sequence in steps S610 and S620.

[0218] Alternatively, as an alternative to method 600, the first LTF and the second LTF do not overlap in the time domain, but overlap in the frequency domain, meaning that the second LTF in the first LTF and the second PPDU occupy the same frequency domain resources. In this alternative, the first sequence and the second sequence can be the same or different.

[0219] Specifically, in this alternative, the first frame in S601a or S601b can be used to indicate the time-domain position of the second LTF, for example, indicating the time-domain position of the first LTF and the interval between the time-domain positions of the first LTF and the second LTF, so that the first LTF and the second LTF do not overlap in the time domain. In addition, the first frame can be used to indicate the frequency-domain position of the second LTF, for example, indicating that the frequency-domain position of the first LTF and the frequency-domain position of the first LTF are the same as the frequency-domain position of the second LTF, so that the first LTF and the second LTF overlap in the frequency domain.

[0220] In the above scheme, when the second LTF in the first LTF and the second PPDU occupy the same frequency domain resources, since they do not overlap in the time domain, there will be no interference regardless of whether the first sequence and the second sequence are the same. In other words, this scheme can reduce mutual interference when multiple APs cooperate and improve the accuracy of channel estimation.

[0221] The methods provided by the embodiments of this application have been described above with reference to Figures 1 to 7. It is understood that, in order to achieve the functions in the above embodiments, the first station and the second station include hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and method steps of the various examples described in conjunction with the embodiments disclosed in this application, this application can be implemented in hardware or a combination of hardware and computer software. Whether a certain function is executed by hardware or by computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0222] Figures 8 and 9 are schematic diagrams of the communication devices provided in the embodiments of this application. These communication devices can be used to implement the functions of the first station and the second station in the above method embodiments, and thus can also achieve the beneficial effects of the above method embodiments. In the embodiments of this application, the communication device can be a first access point, a second access point, a first station, or a second station, or it can be a module (such as a chip) applied to the first access point, the second access point, the first station, or the second station.

[0223] As shown in Figure 8, the communication device 2000 includes a transceiver unit 2020 and a processing unit 2010. The communication device 2000 is used to implement the functions of the first access point, the second access point, the first station, or the second station in the method embodiment shown in Figure 6 above.

[0224] When the communication device 2000 is used to implement the function of the first access point in the method embodiment shown in FIG6: the processing unit 2010 is used to generate a first PPDU, and the transceiver unit 2020 is used to send the first PPDU to the first station.

[0225] When the communication device 2000 is used to implement the function of the second access point in the method embodiment shown in FIG6: the processing unit 2010 is used to generate a second PPDU, and the transceiver unit 2020 is used to send the second PPDU to the second station.

[0226] Optionally, the communication device 2000 may further include a storage unit, which can be used to store program code, program instructions and / or data. The processing unit 2010 can read the instructions and / or data in the storage unit so that the communication device 2000 can implement the aforementioned method embodiments.

[0227] Optionally, the transceiver unit 2020 may include a sending unit and a receiving unit. The sending unit is used to implement the sending operation in the above method embodiment, that is, to execute the sending action of the communication device 2000. The receiving unit is used to implement the receiving operation in the above method embodiment, that is, to execute the receiving action of the communication device 2000.

[0228] It should be noted that the communication device 2000 may include a transmitting unit but not a receiving unit. Alternatively, the communication device 2000 may include a receiving unit but not a transmitting unit. Specifically, it depends on whether the above-described scheme executed by the communication device 2000 includes both transmitting and receiving actions. For a detailed description of the functions performed by the processing unit 2010 and the transceiver unit 2020, please refer to the relevant description in the method shown in Figure 6.

[0229] In this application, the transceiver unit can also be called a transceiver module, which includes a sending module and a receiving module, and the storage unit can also be called a storage module.

[0230] As shown in Figure 9, the communication device 3000 includes a processor 3010 and an interface circuit 3020. The processor 3010 and the interface circuit 3020 are coupled together. It is understood that the interface circuit 3020 can be a transceiver or an input / output interface. Optionally, the communication device 3000 may also include a memory 3030 for storing instructions executed by the processor 3010, or storing input data required by the processor 3010 to execute instructions, or storing data generated after the processor 3010 executes instructions. Sometimes, the interface circuit 3020 can also be understood as part of the processor 3010, in which case the communication device 3000 includes the processor 3010.

[0231] When the communication device 3000 is used to implement the method shown in FIG. 6, the processor 3010 is used to implement the functions of the processing unit 2010, and the interface circuit 3020 is used to implement the functions of the transceiver unit 2020. For example, when the interface circuit 3020 is a transceiver, it may include a transmitter and / or a receiver, respectively used to implement the functions of the transmitting unit and the receiving unit. When the interface circuit 3020 is an input / output interface, it may include an output interface and / or an input interface, respectively used to implement the functions of the transmitting unit and the receiving unit.

[0232] When the communication device 3000 is a chip, the chip includes a processor and a transceiver. The processor can be a processing module integrated on the chip, a microprocessor, or an integrated circuit. The transceiver can be an input / output circuit or a communication interface. The sending operation in the above method embodiments can be understood as the chip's output, and the receiving operation in the above method embodiments can be understood as the chip's input. Optionally, when the communication device 3000 is a chip, it may include a memory, such as the memory built into the chip; alternatively, the communication device 3000 may not include a memory, for example, although the chip is connected to a memory, the memory and the chip are independent of each other.

[0233] Furthermore, when the aforementioned communication device is a chip applied to the first access point (or second access point), the chip implements the functions of the first access point (or second access point) in the above method embodiments. The chip receiving information can be understood as the information being first received by other modules (such as radio frequency modules or antennas) in the first access point (or second access point), and then sent to the chip by these modules. The chip sending information can be understood as the information being first sent to other modules (such as radio frequency modules or antennas) in the first access point (or second access point), and then sent by these modules.

[0234] It is understood that the processor in the embodiments of this application can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor can be a microprocessor or any conventional processor.

[0235] The method steps in the embodiments of this application can be implemented in hardware or in software instructions executable by a processor. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. The storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Alternatively, the ASIC can reside in a base station or terminal. The processor and storage medium can also exist as discrete components in a base station or terminal.

[0236] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0237] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0238] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship. "Including at least one of A, B, and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B, and C.

[0239] In this application, descriptions such as "when," "under the circumstances," "if," and "if" all refer to the device making corresponding actions under certain objective circumstances. They are not time-limited, nor do they require the device to make a judgment action during implementation, nor do they imply any other limitations.

[0240] It should be understood that in the various embodiments of this application, the terms "first," "second," and various numerical designations are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above processes does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

[0241] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0242] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0243] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0244] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0245] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0246] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0247] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, Applied to the first access point, which is the primary access point, including: A first physical layer protocol data unit (PPDU) is generated. The first PPDU includes a first long training field (LTF). The first LTF is used to carry a first sequence. The first sequence is used by a first site for channel estimation. The first sequence and the second sequence are different. The second sequence is used by a second site for channel estimation. The second sequence is carried in a second LTF in a second PPDU. The second PPDU is a PPDU sent from a second access point to a second site. The first LTF and the second LTF occupy the same time-frequency resources. The second access point is a slave access point. Send the first PPDU to the first station.

2. The method according to claim 1, characterized in that, The first sequence and the second sequence are orthogonal.

3. The method according to claim 2, characterized in that, Before generating the first PPDU, the method further includes: A first frame is sent to the second access point. The first frame includes first indication information, which indicates that the sequence carried by the second LTF is orthogonal to the first sequence.

4. The method according to claim 3, characterized in that, The first indication information includes at least one of the following: The guard interval of the symbols carrying the second sequence, the number of subcarriers corresponding to the symbols carrying the second sequence, the number of symbols carrying the second sequence, the subcarrier spacing of the subcarriers corresponding to the symbols carrying the second sequence, and the starting row index of the coefficients used to generate the second sequence in the P matrix.

5. The method according to claim 3 or 4, characterized in that, Before sending the first frame to the second access point, the method further includes: Receive a second frame from the second access point, the second frame being used to indicate parameters of the sequence carried by the second LTF.

6. The method according to claim 1, characterized in that, Both the first sequence and the second sequence are pseudo-random sequences.

7. The method according to claim 6, characterized in that, Before generating the first PPDU, the method further includes: A first frame is sent to the second access point. The first frame includes second indication information, which is used to indicate that the sequence carried by the second LTF is a pseudo-random sequence.

8. The method according to claim 6 or 7, characterized in that, The first sequence is generated based on the first basic service set color (BSS color) to which the first access point belongs, and the second sequence is generated based on the second BSS color to which the second access point belongs.

9. The method according to any one of claims 3, 4, 7 and 8, characterized in that, The first frame is used to initiate the negotiation process of the multi-AP cooperation process, or the first frame is used to initiate the transmission process of the multi-AP cooperation.

10. A communication method, characterized in that, Applied to a second access point, the second access point being a slave access point, including: A second PPDU is generated, which includes a second LTF. The second LTF is used to carry a second sequence. The second sequence is used by the second site for channel estimation. The second sequence is different from the first sequence. The first sequence is used by the first site for channel estimation. The first sequence is carried in the first LTF of the first PPDU. The first PPDU is a PPDU sent from the first access point to the first site. The first LTF and the second LTF occupy the same time-frequency resources. The first access point is the primary access point. Send the second PPDU to the second station.

11. The method according to claim 10, characterized in that, The first sequence and the second sequence are orthogonal.

12. The method according to claim 11, characterized in that, Before generating the second PPDU, the method further includes: A first frame is received from the first access point. The first frame includes first indication information, which indicates that the sequence carried by the second LTF is orthogonal to the first sequence.

13. The method according to claim 12, characterized in that, The first indication information includes at least one of the following: The guard interval of the symbols carrying the second sequence, the number of subcarriers corresponding to the symbols carrying the second sequence, the number of symbols carrying the second sequence, the subcarrier spacing of the subcarriers corresponding to the symbols carrying the second sequence, and the row index of the coefficients used to generate the second sequence in the P matrix.

14. The method according to claim 11 or 12, characterized in that, Before receiving the first frame from the first access point, the method further includes: A second frame is sent to the first access point, the second frame being used to indicate the parameters of the sequence carried by the second LTF.

15. The method according to claim 10, characterized in that, Both the first sequence and the second sequence are pseudo-random sequences.

16. The method according to claim 15, characterized in that, Before generating the second PPDU, the method further includes: A first frame is received from the first access point. The first frame includes second indication information, which indicates that the sequence carried by the second LTF is a pseudo-random sequence.

17. The method according to claim 15 or 16, characterized in that, The first sequence is generated based on the first BSS color to which the first access point belongs, and the second sequence is generated based on the second BSS color to which the second access point belongs.

18. The method according to any one of claims 12, 13, 16, and 17, characterized in that, The first frame is used to initiate the negotiation process of the multi-AP collaboration process, or the first frame is used to initiate the transmission process of the multi-AP collaboration process.

19. A communication method, characterized in that, Applied to a first access point, which is either a primary or secondary access point, including: A first PPDU is generated. The first PPDU includes a first LTF. The first LTF is used to carry a first sequence. The first sequence is used by the first site to perform channel estimation. The first LTF and the second LTF in the second PPDU do not overlap in the time domain. The first LTF and the second LTF in the second PPDU occupy the same frequency domain resources. The second LTF carries a second sequence. The second sequence is used by the second site to perform channel estimation. The second PPDU is a PPDU sent from the second access point to the second site. Send the first PPDU to the first station.

20. The method according to claim 19, characterized in that, The first access point and the second access point are different access points in the multi-AP collaboration process.

21. A communication device, characterized in that, include: The unit is used to perform the method as described in any one of claims 1 to 9, or includes a unit for performing the method as described in any one of claims 10 to 18, or includes a unit for performing the method as described in claim 19 or 20.

22. A communication device, characterized in that, include: A processor coupled to a memory for storing a computer program, the processor for executing the computer program stored in the memory to cause the apparatus to perform the method as claimed in any one of claims 1 to 9, or to cause the apparatus to perform the method as claimed in any one of claims 10 to 18, or to cause the apparatus to perform the method as claimed in claim 19 or 20.

23. A computer-readable storage medium, characterized in that, The storage medium stores a computer program or instructions that, when executed by a communication device, implement the method as described in any one of claims 1 to 9, or the method as described in any one of claims 10 to 18, or the method as described in claim 19 or 20.

24. A computer program product, characterized in that, Includes a computer program that, when run, implements the method as described in any one of claims 1 to 9, or the method as described in any one of claims 10 to 18, or the method as described in claim 19 or 20.

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