Communication method and apparatus

Abstract

The present application relates to the technical field of communications, and in particular to a communication method and apparatus. The present application can be applied to the IEEE 802.11ax standard, the 802.11be standard, the 802.11bn standard, and other standards in the IEEE 802.11 family, such as the 802.15 standard, the 802.11bf standard, the IMMW standard, or the NearLink standard. For any 26-tone DRU, or any 26-tone DRU that can be combined into a larger DRU, the sum of elements in a difference sequence corresponding to the 26-tone DRU is 1 or -1, and an i-th element in the difference sequence may be the ratio of an LTF sequence value corresponding to an i-th subcarrier among subcarriers having an index less than 0 to an LTF sequence value corresponding to an i-th subcarrier among subcarriers having an index greater than 0 in the 26-tone DRU. The LTF sequence satisfying the described condition can reduce the PAPR of the LTF.

Description

Communication method and apparatus

[0001] This application claims priority to the Chinese patent application No. 202411011332.X, filed on July 25, 2024, with the State Intellectual Property Office of China, the Chinese patent application No. 202411011332.X has the invention name of “Communication method and apparatus”, and the whole content of the Chinese patent application No. 202411011332.X is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of communication, and in particular to a communication method and apparatus. BACKGROUND

[0003] Wireless local area network (WLAN) has gone through many generations of standards since its development, including 802.11a / b / g, 802.11n, 802.11ac, 802.11ax, 802.11be and 802.11bn, etc. Among them, 802.11n standard is called high throughput (HT), 802.11ac standard is called very high throughput (VHT), 802.11ax standard is called high efficient (HE), 802.11be standard is called extremely high throughput (EHT), and 802.11bn can be called ultra high reliability (UHR).

[0004] Currently, a low power indoor (LPI) communication mode is defined, which strictly limits the maximum power and maximum frequency spectrum density of transmission. For example, for a station (STA), the maximum power can be 24 dBm, and the maximum power spectrum density can be -1 dBm / MHz. The transmission power of a device is limited by both the maximum power and the maximum power spectrum density. First, the transmission power cannot exceed the maximum power, and the power spectrum density of transmission cannot exceed the maximum power spectrum density. Compared with the maximum power, the maximum power spectrum density is more restrictive, and the maximum power allowed for transmission is usually more limited by the maximum power spectrum density. For a station, when the bandwidth is the maximum 320 MHz, the limit of the maximum power specified by the regulation is reached. Below this bandwidth, only a lower power can be transmitted due to the limit of the maximum power spectrum density. On June 30, 2021, Europe also issued regulations for the 6 GHz spectrum, targeting LPI communication modes, such as a maximum power of 23 dBm and a maximum power spectrum density of 10 dBm / MHz. When the bandwidth does not exceed 20 MHz, the transmission power of the device is mainly limited by the maximum power spectrum density, and when the bandwidth is greater than 20 MHz, the transmission power of the device is mainly limited by the maximum power. Due to the limitation of power spectrum density, the transmission power can be improved by discretizing a limited number of subcarriers (such as 26-tone RUs) to a wider bandwidth, that is, more subcarriers (such as 2 26-tone RUs on odd subcarriers), that is, a distributed resource unit (DRU) or a distributed RU.

[0005] A long training field (LTF) is used for channel estimation, and the LTF is generated based on an LTF sequence. The current LTF sequence is designed for a regular RU (rRU). Therefore, it is urgent to design an LTF sequence for a DRU. SUMMARY

[0006] Embodiments of the present application provide a communication method and device, which effectively reduce the peak to average power ratio (PAPR) of the LTF sequence on the DRU.

[0007] In a first aspect, embodiments of the present application provide a communication method, which can be applied to a first station. The first station can include a wireless local area network (WLAN) device (including a Wi-Fi device or a device involved in the Starlink alliance, etc.), or a chip, functional module, processing system or communication component, etc. provided in the WLAN device. The method comprises:

[0008] The first site determines the LTF sequence, which satisfies the following condition: the LTF sequence value corresponding to the 26-tone DRU satisfies... or or or a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 in a 26-tone DRU. i The LTF sequence value is the value of the i-th subcarrier with an index greater than 0 in the 26-tone DRU. The first station transmits a physical (PHY) layer protocol data unit (PPDU) (or physical layer aggregation process protocol data unit), which includes an LTF, which is determined based on the LTF sequence value corresponding to the assigned DRU.

[0009] For uplink transmissions, if the first site is a non-access point station (non-AP STA), the aforementioned allocated DRU can be a DRU allocated to the first site. For downlink transmissions, if the first site can be an AP, the aforementioned allocated DRU can be a DRU allocated by the AP to the second site.

[0010] In this embodiment of the application, the LTF sequence can reduce the PAPR of the LTF sequence on the DRU by satisfying the above characteristics.

[0011] Secondly, embodiments of this application provide a communication method, which can be applied to a second site. The second site may include a WLAN device (including Wi-Fi devices or devices involved in the StarFlash Alliance, etc.), or may be a chip, functional module, processing system, or communication component disposed within the WLAN device. The method includes:

[0012] The second station receives a PPDU, which includes an LTF. The second station performs channel estimation based on a predefined LTF sequence and the LTF value. The predefined LTF sequence satisfies the following: the LTF sequence value corresponding to the 26-tone DRU satisfies... or or or a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 in a 26-tone DRU. i This is the LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 in the 26-tone DRU.

[0013] In conjunction with the first aspect, in one possible implementation, the LTF is also determined based on the LTF sequence value corresponding to the unassigned DRU, which has an LTF sequence value of 0.

[0014] In this embodiment, an unallocated DRU refers to any DRU in the discrete bandwidth other than the allocated DRUs. For example, for uplink transmission, an unallocated DRU refers to any DRU in the discrete bandwidth other than the DRU allocated to the first site. Similarly, for downlink transmission, an unallocated DRU refers to any DRU in the discrete bandwidth other than the DRU allocated by the AP to at least one first site.

[0015] In conjunction with the first or second aspect, in one possible implementation, the discrete bandwidth of the allocated DRU is 20MHz, and the difference between the index of the i-th subcarrier with an index greater than 0 and the index of the i-th subcarrier with an index less than 0 is 126 or 117; or, the discrete bandwidth of the DRU is 40MHz, and the difference between the index of the i-th subcarrier with an index greater than 0 and the index of the i-th subcarrier with an index less than 0 is 252.

[0016] In this embodiment, the index difference between the i-th subcarrier with an index greater than 0 and the i-th subcarrier with an index less than 0 can effectively reduce the PAPR of the LTF sequence on the DRU by satisfying the above conditions.

[0017] Thirdly, embodiments of this application provide a communication method, which can be applied to a first site. The first site may include a WLAN device (including Wi-Fi devices or devices involved in the StarFlash Alliance, etc.), or may be a chip, functional module, processing system, or communication component disposed within the WLAN device. The method includes:

[0018] The first site determines the LTF sequence, which satisfies the following condition: the LTF sequence value corresponding to the 52-tone DRU satisfies... or or or Among them, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 among the odd-numbered subcarriers in a 52-tone DRU. i The LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 among the odd-numbered subcarriers in a 52-tone DRU; or, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 among the even-numbered subcarriers in a 52-tone DRU. iThe LTF sequence value is the value of the i-th subcarrier with an index greater than 0 in the even-numbered subcarriers of the 52-tone DRU; the first station transmits a PPDU, which includes the LTF, and the LTF is determined based on the LTF sequence value corresponding to the assigned DRU.

[0019] In this embodiment of the application, the LTF sequence can reduce the PAPR of the LTF sequence on the DRU by satisfying the above characteristics.

[0020] Fourthly, embodiments of this application provide a communication method, which can be applied to a second site. The second site may include a WLAN device (including Wi-Fi devices or devices involved in the StarFlash Alliance, etc.), or may be a chip, functional module, processing system, or communication component disposed within the WLAN device. The method includes:

[0021] The second station receives a PPDU, which includes an LTF. The second station performs channel estimation based on a predefined LTF sequence and the LTF value. The predefined LTF sequence satisfies the following: the LTF sequence value corresponding to the 52-tone DRU satisfies... or or or Among them, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 among the odd-numbered subcarriers in a 52-tone DRU. i The LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 among the odd-numbered subcarriers in a 52-tone DRU; or, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 among the even-numbered subcarriers in a 52-tone DRU. i This is the LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 among the even-numbered subcarriers in the 52-tone DRU.

[0022] In conjunction with the third aspect, in one possible implementation, the LTF is also determined based on the LTF sequence value corresponding to the unassigned DRU, which has an LTF sequence value of 0.

[0023] For details regarding unassigned DRUs, please refer to the first or second aspect; they will not be elaborated upon here.

[0024] In conjunction with the third or fourth aspect, in one possible implementation, the discrete bandwidth of the allocated DRU is 80MHz, and the difference between the index of the i-th subcarrier with an index greater than 0 and the index of the i-th subcarrier with an index less than 0 is 500.

[0025] In this embodiment, the index difference between the i-th subcarrier with an index greater than 0 and the i-th subcarrier with an index less than 0 can effectively reduce the PAPR of the LTF sequence on the DRU by satisfying the above conditions.

[0026] Fifthly, embodiments of this application provide a communication device for executing the methods in any one of the first to fourth aspects or any possible implementations thereof. The first communication device includes a module having the capability to execute the methods in any one of the first to fourth aspects or any possible implementations thereof.

[0027] Sixthly, embodiments of this application provide a communication device, which includes a processor and a transceiver. The processor is used to execute the processing steps in the method described in any one of the first to fourth aspects or any possible implementation thereof, and the transceiver is used to execute the sending and receiving steps in the method described in any one of the first to fourth aspects or any possible implementation thereof.

[0028] In a seventh aspect, embodiments of this application provide a communication device including a logic circuit and an interface, wherein the logic circuit and the interface are coupled; the interface is used to input and / or output information, and the logic circuit is used to perform processing steps in the method described in any one of the first to fourth aspects or any possible implementation thereof.

[0029] Eighthly, embodiments of this application provide a computer-readable storage medium for storing a computer program that, when run on a computer, causes the methods described in any of the first to fourth aspects or any possible implementation thereof to be executed.

[0030] Ninthly, embodiments of this application provide a computer program product that, when run on a computer, causes the methods described in any of the first to fourth aspects or any possible implementation thereof to be executed.

[0031] In a tenth aspect, embodiments of this application provide a communication system comprising a first station and a second station. The first station is configured to perform the method described in the first aspect or any possible implementation thereof, and the second station is configured to perform the method described in the second aspect or any possible implementation thereof.

[0032] Eleventhly, embodiments of this application provide a communication system including a first station and a second station. The first station is used to execute the method described in the third aspect or any possible implementation thereof, and the second station is used to execute the method described in the fourth aspect or any possible implementation thereof. Attached Figure Description

[0033] Figure 1 is a schematic diagram of the architecture of the communication system provided in an embodiment of this application;

[0034] Figure 2 is a schematic diagram of the relationship between spatial flow and time provided in an embodiment of this application;

[0035] Figure 3 is a schematic diagram of a 4x HE LTF sequence with a bandwidth of 20MHz provided in an embodiment of this application;

[0036] Figure 4 is a schematic diagram of a 4x HE LTF sequence with a bandwidth of 40MHz provided in an embodiment of this application;

[0037] Figure 5 is a schematic diagram of a 4x HE LTF sequence with an 80MHz bandwidth provided in an embodiment of this application;

[0038] Figure 6 is a flowchart illustrating the communication method provided in an embodiment of this application;

[0039] Figure 7 is a schematic diagram of a communication device provided in an embodiment of this application;

[0040] Figure 8 is a schematic diagram of another structure of the communication device provided in an embodiment of this application;

[0041] Figure 9 is a schematic diagram of another structure of the communication device provided in the embodiments of this application. Detailed Implementation

[0042] To facilitate understanding of the technical solution of this application, the application will be further described below with reference to the accompanying drawings.

[0043] The terms "first" and "second," etc., used in the specification, claims, and drawings of this application are used only to distinguish different objects and not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0044] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] In this application, "at least one (item)" refers to one or more, "more than one" refers to two or more, "at least two (items)" refers to two or three or more, and "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. "Or" indicates that there can be two relationships, such as only A exists or only B exists; when A and B are not mutually exclusive, it can also mean that there are three relationships, such as only A exists, only B exists, or both A and B exist simultaneously. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items. For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c".

[0046] In this application, "send" and "receive" indicate the direction of signal transmission. For example, "send information to XX" can be understood as the destination of the information being XX, which can include direct transmission via the air interface or indirect transmission via the air interface from other units or modules. "Receive information from YY" can be understood as the source of the information being YY, which can include direct reception from YY via the air interface or indirect reception from YY via the air interface from other units or modules. "Send" can also be understood as the "output" of a chip interface, and "receive" can also be understood as the "input" of a chip interface. In other words, sending and receiving can occur between devices, such as between network devices and terminal devices, or within a device, such as between components, modules, chips, software modules, or hardware modules within the device via buses, traces, or interfaces.

[0047] The following describes the system involved in the embodiments of this application.

[0048] The technical solutions provided in this application can be applied to WLAN systems, such as Wi-Fi. For example, the technical solutions provided in this application can be applied to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series protocols (or standards), such as the 802.11be protocol, the 802.11bn protocol (or Wi-Fi 8, also known as Ultra High Reliability (UHR) or Ultra High Reliability and Throughput (UHRT)), or next-generation protocols of the 802.11bn protocol, or protocols supporting ambient power (AMP), etc., and will not be listed exhaustively. The technical solutions provided in this application can also be applied to wireless personal area networks (WPANs) based on millimeter wave (MMW) technologies, such as integrated millimeter wave (IMMW) and ultra-wideband (UWB) technologies. The technical solutions provided in the embodiments of this application can be applied to the IEEE 802.15 series protocols, such as the 802.15.4a, 802.15.4z, or 802.15.4ab protocols, or future UWB WPAN protocols, etc., and will not be listed one by one. The technical solutions provided in the embodiments of this application can also be applied to the Spark Link or NearLink standard protocol. The technical solutions provided in the embodiments of this application can also be applied to the following communication systems, such as Internet of Things (IoT) systems, vehicle-to-everything (V2X, where X can represent anything), device-to-device (D2D), narrowband Internet of Things (NB-IoT) systems, long term evolution (LTE) systems, 5th generation (5G) communication systems, and new communication systems that will emerge in the future development of communication, etc.For example, V2X can include vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P), or vehicle-to-network (V2N) communication.

[0049] WLAN systems can provide high-speed, low-latency transmission. As WLAN application scenarios continue to evolve, WLAN systems will be applied to more scenarios or industries, such as the Internet of Things industry, the Internet of Vehicles industry, the banking industry, enterprise offices, stadiums and exhibition halls, concert halls, hotel rooms, dormitories, hospital wards, classrooms, shopping malls, squares, streets, production workshops and warehouses, etc. Of course, devices that support WLAN communication or sensing (such as access points or sites) can be sensor nodes in smart cities (such as smart water meters, smart electricity meters, and smart air monitoring nodes), smart devices in smart homes (such as smart cameras, projectors, displays, televisions, speakers, refrigerators, and washing machines), nodes in the Internet of Things (IoT), entertainment terminals (such as wearable devices for augmented reality (AR) and virtual reality (VR), smart devices in smart offices (such as printers, projectors, loudspeakers, and speakers), vehicle-to-everything (V2X) devices, infrastructure in daily life scenarios (such as vending machines, self-service navigation kiosks in supermarkets, self-service checkout machines, and self-service ordering machines), and equipment in large sports and music venues.

[0050] Although the embodiments of this application primarily use WLAN as an example, especially networks applied to the IEEE 802.11 series of standards, the various aspects involved in the embodiments of this application can be extended to other networks employing various standards or protocols. For example, Bluetooth, high-performance radio LAN (HIPERLAN) (a wireless standard similar to the IEEE 802.11 standard), and wide area networks (WANs) or other networks now known or to be developed in the future.

[0051] In one possible implementation, the method provided in this application embodiment can be implemented by a communication device in a communication system. For example, the communication device can be an access point (AP) or a station (STA).

[0052] An Access Point (AP) is a device with wireless communication capabilities that supports communication, sensing, or power transmission using WLAN protocols. It has the function of communicating or sensing with other devices in a WLAN network (such as non-access point stations (non-AP STAs) or other access points), and can also have the function of communicating, sensing, or transmitting power with other devices. Alternatively, an access point acts as a bridge connecting wired and wireless networks, primarily connecting various wireless network clients together and then connecting the wireless network to an Ethernet network. In a WLAN system, an access point can be called an Access Point Station (AP STA). This wireless communication device can be a complete device or a chip, processing system, or functional module installed within a complete device. Devices with these chips, processing systems, or functional modules can implement the methods and functions of the embodiments in this application under the control of the chips, processing systems, or functional modules. The AP in the embodiments of this application is a device that provides services to non-AP STAs and can support 802.11 series protocols or subsequent protocols. For example, an access point can be an access point for a terminal (such as a mobile phone) to enter a wired (or wireless) network, mainly deployed in homes, buildings, and parks, with a typical coverage radius of tens to hundreds of meters. Of course, it can also be deployed outdoors. Another example is that an AP can be a communication entity such as a communication server, router, switch, or bridge; APs can include various forms of macro base stations, micro base stations, and repeater stations. Of course, an AP can also be a chip, processing system, or module within the above-mentioned devices, thereby implementing the methods and functions of the embodiments of this application.

[0053] A Station-Style (STA) is a device with wireless communication capabilities that supports communication, sensing, or power transmission using the WLAN protocol. It has the ability to communicate, sense, or transmit power with other non-AP STAs or access points in a WLAN network. In a WLAN system, a station can be called a non-access point station (non-AP STA). For example, an STA is any user communication device that allows a user to communicate with an AP (Access Point) or sense or transmit power, and thus communicate with the WLAN. This wireless communication device can be a complete device, or it can be a chip, processing system, or functional module installed in a complete device. Devices with these chips, processing systems, or functional modules can implement the methods and functions of the embodiments of this application under the control of the chips, processing systems, or functional modules. For example, an STA can be a wireless communication chip, a wireless sensor, or a wireless communication terminal, and can also be referred to as a user. Furthermore, an STA can be a mobile phone supporting Wi-Fi communication, a tablet computer supporting Wi-Fi communication, a set-top box supporting Wi-Fi communication, a smart TV supporting Wi-Fi communication, a smart wearable device supporting Wi-Fi communication, an in-vehicle communication device supporting Wi-Fi communication, and a computer supporting Wi-Fi communication. Of course, STA can also be a chip, processing system, or module in the various types of devices described above, thereby implementing the methods and functions of the embodiments of this application.

[0054] For example, the communication systems to which the methods provided in this application can be applied may include access points and stations. For instance, this application can be applied to scenarios of communication or sensing between APs and STAs, between APs, or between STAs in a WLAN, and this application does not limit this. Optionally, an AP can communicate or sense with a single STA, or an AP can communicate or sense with multiple STAs simultaneously. Specifically, communication or sensing between an AP and multiple STAs can be further divided into downlink transmission where the AP simultaneously sends signals to multiple STAs, and uplink transmission where multiple STAs send signals to the AP. The communication protocols between APs and STAs, between APs, and between STAs can support WLAN communication protocols, which may include IEEE 802.11 series protocols, such as the 802.11bn protocol, and of course, protocols after 802.11bn.

[0055] Figure 1 is a schematic diagram of the architecture of a communication system provided in an embodiment of this application. The communication system may include one or more APs and one or more STAs. Figure 1 shows two access points, such as AP1 and AP2, and three stations, such as STA1 (or non-AP STA1), STA2 (or non-AP STA2), and STA3 (or non-AP STA3). As an example, the method provided in this embodiment can be applied to data communication, sensing, or power transmission between an AP and one or more STAs, such as the communication or sensing between AP1 and STA1 as shown in Figure 1, and the communication or sensing between AP1 and STA1 / STA2 as shown in Figure 1. As another example, the method provided in this embodiment can be applied to communication between APs, such as the communication or sensing between AP1 and AP2 as shown in Figure 1. As yet another example, the method provided in this embodiment can be applied to communication or sensing between STAs, such as the communication or sensing between STA2 and STA3 as shown in Figure 1.

[0056] Figure 1 uses STA (Mobile Phone) and AP (Router) as an example, and does not imply a limitation on the types of APs and STAs in this application embodiment. Furthermore, the number of APs and STAs shown in Figure 1 is merely an example; in a specific implementation, the number of APs or STAs may be more or less, and this application embodiment does not limit this.

[0057] The following describes the terms used in the embodiments of this application.

[0058] 1. LTF and LTF sequences

[0059] LTF refers to the time domain dimension, while LTF sequence refers to the frequency domain dimension. An LTF sequence undergoes an inverse Fourier transform to form an LTF in the time domain. Therefore, an LTF is generated based on an LTF sequence. This LTF includes one or more OFDM symbols.

[0060] The LTF sequence is designed for specific bandwidths and specifies the LTF sequence value for each subcarrier during LTF transmission. The LTF sequence is used for channel estimation, or in other words, the LTF is used for channel estimation.

[0061] For scenarios with multiple spatial streams, LTF can be used for channel estimation of each spatial stream. The bandwidth used to transmit LTF includes data subcarriers and pilot subcarriers.

[0062] In one possible implementation, the data subcarriers are transmitted as follows:

[0063] To ensure LTF orthogonality among the streams, the P matrix can be multiplied by the LTF sequence value. For example, the k-th subcarrier in the bandwidth corresponds to the k-th LTF sequence value in the LTF sequence. k The nth OFDM symbol corresponding to the mth spatial flow is multiplied by the element in the mth row and nth column of the P matrix.

[0064] For example, the P matrix is ​​shown below:

[0065] Figure 2 is a schematic diagram illustrating the relationship between spatial flow and time according to an embodiment of this application. In Figure 2, "1" or "-1" corresponds to the P matrix. For example, "1, -1, 1, 1" in the first row of Figure 2 corresponds to the first row of the P matrix, and so on. The times shown in Figure 2, such as 0 ns, -400 ns, -200 ns, or -600 ns, represent the cyclic shift diversity (CSD) corresponding to each spatial flow. Figure 2 also exemplarily illustrates the relationship between different spatial flows and the P matrix.

[0066] The k-th subcarrier experiences channel H k Then, the receiver receives the frequency domain signal Y. k It can be represented as: Y k =H k ×P 4×4 ×LTF k

[0067] Because of P 4×4 The matrix is ​​an orthogonal matrix, that is... I is the identity matrix. It is P 4×4 The conjugate transpose of the matrix. Therefore, the channel on the k-th subcarrier. The multiple-in multiple-out (MIMO) channel corresponding to the k-th subcarrier can be estimated using the above method.

[0068] In one possible implementation, the pilot subcarrier is transmitted as follows:

[0069] The k-th subcarrier in the bandwidth corresponds to the k-th LTF sequence value in the LTF sequence. k The nth OFDM symbol corresponding to the mth spatial flow is multiplied by the element in the mth row and nth column of the R matrix. For example, R(m, n) = P(1, n). That is, each row of the R matrix is ​​equal to the first row of the P matrix. Of course, as standards evolve, each row of the R matrix can also be equal to the second or third row of the P matrix, etc., which will not be listed here. Alternatively, as standards evolve, the R matrix can be designed separately; this application does not limit this approach.

[0070] LTF sequences can be categorized into 1x, 2x, and 4x sequences. In a 1x LTF sequence, there must be at least three zeros between two adjacent non-zero elements; in a 2x LTF sequence, there must be at least one zero between two adjacent non-zero elements; and in a 4x LTF sequence, there can be consecutive non-zero elements. The 4x LTF sequence has the densest concentration of non-zero elements, thus providing the most accurate channel estimation. Examples of 4x sequences at different bandwidths are given below.

[0071] Figure 3 is a schematic diagram of a 4x HE LTF sequence with a 20MHz bandwidth provided in an embodiment of this application. Taking a subcarrier spacing of 78.125kHz as an example, a 20MHz bandwidth can correspond to 256 subcarriers, whose indices are denoted as -128:127. Figure 3 exemplarily shows the LTF sequence values ​​corresponding to the subcarriers with indices -122:122, while the LTF sequence values ​​corresponding to other subcarriers with indices not shown are 0.

[0072] Figure 4 is a schematic diagram of a 4x HE LTF sequence with a bandwidth of 40MHz provided in an embodiment of this application. Taking a subcarrier spacing of 78.125kHz as an example, a 40MHz bandwidth can correspond to 512 subcarriers, whose indices are denoted as -256:255. Figure 4 exemplarily shows the LTF sequence value corresponding to the subcarrier with index -244:244, while the LTF sequence value corresponding to other subcarriers without indices is 0.

[0073] Figure 5 is a schematic diagram of a 4x HE LTF sequence with an 80MHz bandwidth provided in an embodiment of this application. Taking a subcarrier spacing of 78.125kHz as an example, the 80MHz bandwidth can correspond to 1024 subcarriers, whose indices are denoted as -512:511. Figure 5 exemplarily shows the LTF sequence values ​​corresponding to the subcarriers with indices -500:500, while the LTF sequence values ​​corresponding to other subcarriers without indices are 0.

[0074] In this embodiment, the RU used to transmit the LTF is the same as the RU used to transmit the data field. For example, if the RU used to transmit the data field is RU1, then the RU used to transmit the LTF is also RU1. The LTF sequence value carried on each subcarrier in the RU used to transmit the LTF is determined by the LTF sequence.

[0075] 2. Distributed Resource Unit (DRU)

[0076] DRU comprises multiple subcarriers discrete in the frequency domain, or multiple subcarriers discrete indices (or index values), or multiple subcarriers with discontinuous indices. These discrete subcarriers can be partially discrete or completely discrete. For example, some subcarriers may be frequency-continuous, while others may be frequency-discontinuous. Furthermore, these discrete subcarriers can be completely frequency-discontinuous. The phrase "frequency-continuous" can also be interpreted as "the indices of the subcarriers are continuous," and "frequency-discontinuous" can also be interpreted as "the indices of the subcarriers are discontinuous."

[0077] DRUs are commonly used in uplink multi-user transmissions. By interleaving discrete RUs with multiple users, the transmission power of each user is increased within a given bandwidth. For example, the maximum power spectral density can be limited to a transmission power of no more than P mW per 1MHz. Considering a subcarrier spacing of 78.125kHz, 1MHz contains 12.8 (approximately 13) subcarriers. Since the average power of each subcarrier is the same during a single transmission, observing any consecutive 13 subcarriers, the maximum number of subcarriers carrying the signal determines the average power of each subcarrier, and thus the transmission power. For instance, with a 20MHz bandwidth (242 subcarriers), if a maximum of 5 subcarriers in any consecutive 13 subcarriers carry the signal, then the average power of each subcarrier will be P / 5mW. Considering there are 26 subcarriers carrying the signal, the total transmission power will be (P / 5)*26mW.

[0078] 3. DRU Subcarrier Planning (DRU toneplan)

[0079] DRU subcarrier planning can be designed based on the following principles: (1) For the same bandwidth, the size and number of DRUs are the same as those of rRUs; (2) For different sizes, the hierarchical relationship between DRUs is the same as that of rRUs; (3) DRUs can reuse existing RU indication tables.

[0080] Table 1 provides an example of subcarrier planning with a discrete bandwidth of 20 MHz.

[0081] Table 1

[0082] Table 2 provides an example of subcarrier planning with a discrete bandwidth of 40 MHz.

[0083] Table 2

[0084] Table 3 exemplarily illustrates subcarrier planning for a discrete bandwidth of 80MHz. For subcarrier planning at 80MHz, each 52-tone DRU can still be considered as a combination of two 26-tone DRUs, with the two square brackets in Table 3 indicating the index of a 26-tone DRU. However, subcarrier planning at 80MHz no longer supports calling 26-tone DRUs. The form of the subcarrier index of the 52-tone DRU shown in Table 3 is merely an example and is not intended to limit the embodiments of this application.

[0085] Table 3

[0086] The pilot subcarriers in a DRU can be designed based on the following principles: (1) For each size of DRU, the number of pilot subcarriers is the same as that of an rRU. For example, a 26-tone DRU contains 2 pilot subcarriers; a 52-tone DRU contains 4 pilot subcarriers; a 106-tone DRU contains 4 pilot subcarriers; a 242-tone DRU contains 8 pilot subcarriers; and a 484-tone DRU contains 16 pilot subcarriers. (2) There is a hierarchical relationship between the pilot subcarriers of each size of DRU, and the hierarchical relationship is the same as that of an rRU. For example, the four pilot subcarriers of a 52-tone DRU are composed of the pilot subcarriers of the two 26-tone DRUs it contains; the four pilot subcarriers of a 106-tone DRU are contained within the eight pilot subcarriers of the two 52-tone DRUs it contains; the eight pilot subcarriers of a 242-tone DRU are composed of the pilot subcarriers of the two 106-tone DRUs it contains; and the sixteen pilot subcarriers of a 484-tone DRU are composed of the pilot subcarriers of the two 242-tone DRUs it contains.

[0087] Table 4 exemplarily illustrates an index configuration for pilot subcarriers with a bandwidth of 20 MHz. The table can be divided into two parts: the upper part contains 9 rows, each representing the index of a subcarrier in a 26-tone DRU with an index less than 0 (or the index of the negative half-frequency); the lower part contains 9 rows, each representing the index of a subcarrier in a 26-tone DRU with an index greater than 0 (or the index of the positive half-frequency). The subcarrier indices shown in bold are the pilot subcarrier indices of the 26-tone DRU.

[0088] Table 4

[0089] The relative positions of the pilot subcarriers in each DRU are shown in Table 5. For example, dP26-1(2,15) indicates that the 2nd and 15th subcarriers in 26-tone DRU 1 are pilot subcarriers. In terms of frequency from low to high, the subcarrier with the smallest index in 26-tone DRU 1 is the 1st subcarrier. `sort` indicates sorting to obtain the relative positions of the pilot subcarriers in the corresponding DRU. For example, `sort([dP26_1dP26_2])` indicates that the four pilot subcarriers of 52-tone DRU 1 are composed of pilot subcarriers from 26-tone DRU 1 and 26-tone DRU 2, or in other words, the relative positions of the pilot subcarriers in 52-tone DRU 1 are the relative positions of the two pilot subcarriers in 26-tone DRU 1 and the two pilot subcarriers in 26-tone DRU 2 after sorting them in order of frequency from low to high. For example, `sort([dP52_1([1,3])dP52_2([2,4])])` indicates that the four pilot subcarriers of 106-tone DRU 1 are ordered from low to high frequency, representing the first and third pilot subcarriers in 52-tone DRU 1, and the second and fourth pilot subcarriers in 52-tone DRU 2. After sorting these four pilot subcarriers, their relative positions within 106-tone DRU 1 are determined. Other examples will not be detailed here.

[0090] Table 5

[0091] The following describes the methods involved in the embodiments of this application.

[0092] This application provides a communication method and apparatus that redesigns the LTF sequence based on DRU, effectively reducing the PAPR of the LTF sequence on DRU.

[0093] Figure 6 is a flowchart illustrating the communication method provided in an embodiment of this application. The first and second stations involved in this method are as described above and will not be detailed here. As an example, the first station is a non-AP STA, and the second station is an AP. As another example, the first station is an AP, and the second station is a non-AP STA. Of course, both the first and second stations can be non-AP STAs, etc., which will not be listed here. As shown in Figure 6, the method includes:

[0094] 601. The first site determines the LTF sequence.

[0095] The first station determines the LTF sequence, including: the first station determines the LTF sequence based on discrete bandwidth and sequence pattern, wherein the sequence pattern includes a 1x LTF sequence pattern, a 2x LTF sequence pattern, or a 4x LTF sequence pattern. Optionally, for a DRU, the LTF sequence may only have a 4x LTF sequence pattern, so when the first station knows that the RU it uses is a DRU, it can determine the LTF sequence only based on the discrete bandwidth of the DRU.

[0096] The LTF sequence shown in the embodiments of this application can satisfy:

[0097] As one possible implementation, the LTF sequence value corresponding to the 26-tone DRU satisfies or or or Or, in other words, the LTF sequence value corresponding to the 26-tone DRU satisfies or or

[0098] Among them, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 in a 26-tone DRU. i This is the LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 in the 26-tone DRU.

[0099] In a 26-tone DRU, the 26 subcarriers are discretely distributed throughout the bandwidth. There are 13 subcarriers with an index less than 0 (or negative half-frequency) and 13 subcarriers with an index greater than 0 (or positive half-frequency).

[0100] In order of frequency from low to high, or in order of frequency from high to low, the above a i For the LTF sequence value corresponding to the i-th subcarrier among the 13 subcarriers with an index less than 0, the above b i This is the LTF sequence value corresponding to the i-th subcarrier among the 13 subcarriers with an index greater than 0. i =1 or -1, b i =1 or -1.

[0101] Alternatively, the difference X is the index of the i-th subcarrier with an index greater than 0 and the index of the i-th subcarrier with an index less than 0. X is a positive integer. For example, with a discrete bandwidth of 20MHz, X = 126 or 117. Another example is a discrete bandwidth of 40MHz, where X = 252. Therefore, the above c... i This is the ratio of the two LTF sequence values ​​corresponding to two subcarriers with an index difference of X, or c.i This is referred to as the i-th element in the difference sequence corresponding to the two subcarriers mentioned above. The sum of all elements in the difference sequence corresponding to the 26-tone DRU is -1 or 1. The name of the difference sequence shown here is merely an example and is not intended to limit the embodiments of this application. The value of X can vary with different subcarriers; the value of X is merely an example, and the value of X can change as the subcarrier index of the DRU changes.

[0102] For example, in ascending order of frequency, the LTF sequence values ​​corresponding to the 13 subcarriers with indices less than 0 are [a1, a2, a3, ..., a...]. 13 The LTF sequence values ​​corresponding to the 13 subcarriers with indices greater than 0, arranged in ascending order of frequency, are [b1, b2, b3, ..., b...]. 13 The difference sequence corresponding to the 26-tone DRU is [c1,c2,c3,…,c…]. 13 For example, or For example, the difference sequence corresponding to a 26-tone DRU includes 6 ones and 7 ones, or 7 ones and 6 ones.

[0103] The LTF sequence value corresponding to a 26-tone DRU is the portion of the LTF sequence that corresponds to each subcarrier in that 26-tone DRU. That is, a 26-tone DRU corresponds to 26 LTF sequence values. For example, if the subcarrier indices of a 26-tone DRU are [-120:9:-12] and [6:9:114], then the LTF sequence values ​​corresponding to that 26-tone DRU include: the LTF sequence value corresponding to the subcarrier with index -120, the LTF sequence value corresponding to the subcarrier with index -111, the LTF sequence value corresponding to the subcarrier with index -102, the LTF sequence value corresponding to the subcarrier with index -93, and so on. These will not be listed individually here.

[0104] For implementation method 1, as an example, the LTF sequence can satisfy the above characteristics for each 26-tone DRU under discrete bandwidth. For instance, 20MHz can include 9 26-tone DRUs, and the LTF sequence can satisfy the above characteristics for any one of these 9 26-tone DRUs. Similarly, 40MHz can include 18 26-tone DRUs, and the LTF sequence can satisfy the above characteristics for any one of these 18 26-tone DRUs.

[0105] Regarding implementation method 1, as another example, for DRUs of other sizes under discrete bandwidth (DRUs of other sizes containing 26-tone DRUs), or for 26-tone DRUs that can be merged into a larger DRU, the LTF sequence can satisfy the above characteristics. For example, 20MHz can include 9 26-tone DRUs, or 4 52-tone DRUs, or 2 106-tone DRUs. A 52-tone DRU is obtained by merging 2 26-tone DRUs, that is, 8 out of the above 9 26-tone DRUs are used to merge into a 52-tone DRU. For any one of the 8 26-tone DRUs that can be merged into a 52-tone DRU, the LTF sequence can satisfy the above characteristics. A 106-tone DRU is obtained by merging 4 26-tone DRUs, that is, 8 out of the above 9 26-tone DRUs are used to merge into a 106-tone DRU. For any one of the eight 26-tone DRUs that can be merged into a 106-tone DRU, the LTF sequence can satisfy the above characteristics. For example, 40MHz can include 18 26-tone DRUs, or eight 52-tone DRUs, or four 106-tone DRUs, or two 242-tone DRUs. Of the 18 26-tone DRUs, 16 are used to merge into a 52-tone DRU (or a 106-tone DRU, or a 242-tone DRU). For any one of these 16 26-tone DRUs, the LTF sequence can satisfy the above characteristics.

[0106] The above implementation method 1 can be applied to discrete bandwidths including 26-tone DRUs in subcarrier planning.

[0107] By satisfying the above characteristics, LTF sequences can achieve a lower PAPR on DRU.

[0108] As another possible implementation, the LTF sequence value corresponding to the 52-tone DRU satisfies or or or In other words, the LTF sequence value corresponding to 52-tone DRU satisfies or or ai =1 or -1, b i =1 or -1.

[0109] Among them, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 among the odd-numbered subcarriers in a 52-tone DRU. i This is the LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 among the odd-numbered subcarriers in a 52-tone DRU. Alternatively, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 among the even-numbered subcarriers in a 52-tone DRU. i This is the LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 among the even-numbered subcarriers in the 52-tone DRU.

[0110] In a 52-tone DRU, the 52 subcarriers can be discretely distributed across the bandwidth. Among the odd-numbered subcarriers, 13 have indices less than 0, and 13 have indices greater than 0. Similarly, among the even-numbered subcarriers, 13 have indices less than 0, and 13 have indices greater than 0. That is, there are a total of 26 odd-numbered subcarriers and 26 even-numbered subcarriers in a 52-tone DRU. Therefore, the relevant explanations regarding 52-tone DRUs can also refer to Implementation Method 1 above.

[0111] As an example, in order of frequency from low to high, or in order of frequency from high to low, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 among the odd-numbered subcarriers in a 52-tone DRU. i This is the LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 among the odd-numbered subcarriers in the 52-tone DRU.

[0112] Alternatively, in a 52-tone DRU, the difference Y is the index of the i-th subcarrier with an index greater than 0 among the odd-numbered subcarriers and the index of the i-th subcarrier with an index less than 0 among the odd-numbered subcarriers. Y is a positive integer. For example, with a discrete bandwidth of 80MHz, Y = 500. i This is the ratio of the two LTF sequence values ​​corresponding to two subcarriers with an index difference of Y, or c. iThis refers to the i-th element in the difference sequence corresponding to the two subcarriers mentioned above. The value of Y can vary depending on the subcarrier; the value of Y is only an example. As the subcarrier index of the DRU changes, the value of Y can also change. This example uses 80MHz. Implementation method 2 can be applied to discrete bandwidths that include 52-tone DRUs in the subcarrier planning, such as 20MHz or 40MHz, etc., which will not be listed here.

[0113] For example, in a 52-tone DRU, the LTF sequence values ​​corresponding to the 13 subcarriers with indices less than 0 in the odd-numbered subcarriers are [a1, a2, a3, ..., a...]. 13 The LTF sequence values ​​corresponding to the 13 subcarriers with indices greater than 0 in the odd-numbered subcarriers mentioned above are [b1, b2, b3, ..., b...]. 13 The difference sequence corresponding to 52-tone DRU is [c1,c2,c3,…,c]. 13 For example, or

[0114] As another example, in order of frequency from low to high, or in order of frequency from high to low, a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 among the even-numbered subcarriers in a 52-tone DRU. i This is the LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 among the even-numbered subcarriers in the 52-tone DRU.

[0115] Alternatively, in a 52-tone DRU, the difference Y is the index of the i-th subcarrier with an index greater than 0 among the even-numbered subcarriers and the index of the i-th subcarrier with an index less than 0 among the even-numbered subcarriers. Y is a positive integer. For example, with a discrete bandwidth of 80MHz, Y = 500. i This is the ratio of the two LTF sequence values ​​corresponding to two subcarriers with an index difference of Y, or c. i It is the i-th element in the difference sequence corresponding to the two subcarriers mentioned above.

[0116] For example, in a 52-tone DRU, the LTF sequence values ​​corresponding to the 13 subcarriers with indices less than 0 in the even-numbered subcarriers are [a1, a2, a3, ..., a...]. 13 The LTF sequence values ​​corresponding to the 13 subcarriers with indices greater than 0 in the even-numbered subcarriers mentioned above are [b1, b2, b3, ..., b...]. 13 The difference sequence corresponding to 52-tone DRU is [c1,c2,c3,…,c]. 13For example, or

[0117] For example, the subcarrier indices of a 52-tone DRU are [-483:36:-51, 17:36:449, -467:36:-35, 33:36:465]. Following the order of frequency from low to high, the lowest frequency subcarrier is designated as the first subcarrier in the 52-tone DRU. The index of the odd-numbered subcarriers in the 52-tone DRU is [-483:36:-51, 17:36:449], and the index of the even-numbered subcarriers is [-467:36:-35, 33:36:465]. a1 is the LTF sequence value corresponding to the subcarrier at index -483, b1 is the LTF sequence value corresponding to the subcarrier at index 17, a2 is the LTF sequence value corresponding to the subcarrier at index -447, b2 is the LTF sequence value corresponding to the subcarrier at index 53, and so on. These will not be listed individually here. Alternatively, a1 is the LTF sequence value corresponding to the subcarrier at index -467, b1 is the LTF sequence value corresponding to the subcarrier at index 33, a2 is the LTF sequence value corresponding to the subcarrier at index -431, b2 is the LTF sequence value corresponding to the subcarrier at index 69, and so on. They will not be listed one by one here.

[0118] For implementation method 2, the LTF sequence value corresponding to 52-tone DRU can also meet the requirements. or or or or or a i b is the LTF sequence value corresponding to the i-th subcarrier with an index less than 0 in a 52-tone DRU. i This is the LTF sequence value corresponding to the i-th subcarrier with an index greater than 0 in the 52-tone DRU.

[0119] Since the sum of the elements in the difference sequence corresponding to the odd-numbered subcarrier in a 52-tone DRU is 1 or -1, and the sum of the elements in the difference sequence corresponding to the even-numbered subcarrier in a 52-tone DRU is 1 or -1, the sum of the elements in the difference sequence can be 2, 0, or -2 for a 52-tone DRU. For an explanation of the LTF sequence value, please refer to the description of implementation method 2 above; it will not be elaborated upon here.

[0120] For each 52-tone DRU with discrete bandwidth, the LTF sequence can satisfy the above characteristics. This results in a lower PAPR for the LTF sequence on the DRU.

[0121] For example, the first site determines the LTF sequence by: determining the LTF sequence based on the discrete bandwidth. The LTF sequence can be designed for different discrete bandwidths, meaning different discrete bandwidths correspond to different LTF sequences, thus the first site can determine the corresponding LTF sequence based on the discrete bandwidth. For discrete bandwidths of 20MHz or 40MHz, the LTF sequence description can be found in Implementation Method 1 or Implementation Method 2 above. For discrete bandwidths of 80MHz, the LTF sequence description can be found in Implementation Method 2 above. Since 26-tone DRUs are not supported in 80MHz subcarrier planning, the minimum size DRU in 80MHz subcarrier planning is 52-tone DRU. Of course, when 26-tone DRUs are supported in 80MHz subcarrier planning, the description of the LTF sequence can also be found in Implementation Method 1.

[0122] For example, the first station determines the LTF sequence by: the first station determining the LTF sequence based on discrete bandwidth and sequence pattern, wherein the sequence pattern includes a 1x LTF sequence pattern, a 2x LTF sequence pattern, or a 4x LTF sequence pattern.

[0123] Optionally, for a DRU, the LTF sequence can only have a 4x LTF sequence mode, so that when the first station learns that the RU it is using is a DRU, it can determine the LTF sequence only based on the discrete bandwidth of the DRU.

[0124] In one possible implementation, the method shown in Figure 6 may also include:

[0125] Prior to step 601, the first station receives a trigger frame, which includes discrete bandwidth, identifier information of the first station, and resource allocation information of the first station, indicating the size and location of the DRU allocated to the first station. The first station can learn about the discrete bandwidth, the size and location of the DRU allocated to the first station from the trigger frame.

[0126] 602. The first station sends a PPDU, which includes an LTF (Long-Term Filter), determined based on the LTF sequence value corresponding to the assigned DRU. Correspondingly, the second station receives the PPDU, which also includes the LTF.

[0127] For example, the LTF is also determined based on the LTF sequence value corresponding to the unassigned DRU. The LTF sequence value corresponding to the unassigned DRU can be 0. An unassigned DRU refers to any DRU in the discrete bandwidth other than the assigned DRUs. For uplink transmission, an unassigned DRU refers to any DRU in the discrete bandwidth other than the DRU assigned to the first site. Similarly, for downlink transmission, an unassigned DRU refers to any DRU in the discrete bandwidth other than the DRUs assigned by the AP to at least one first site.

[0128] For uplink orthogonal frequency division multiple access (OFDMA), each subcarrier of the DRU allocated to the first site corresponds to an LTF sequence value in the LTF sequence, which can be 1 or -1. The LTF sequence value corresponding to each subcarrier of the unallocated DRU is 0, or in other words, the signal carried on each subcarrier of the unallocated DRU is 0.

[0129] For downlink OFDMA, each subcarrier of an allocated DRU corresponds to an LTF sequence value in the LTF sequence, which can be 1 or -1. The LTF sequence value for each subcarrier of an unallocated DRU is 0. For example, in a discrete bandwidth of 20MHz, where eight 26-tone DRUs within this 20MHz are used to transmit PPDUs, if one 26-tone DRU within this 20MHz is unallocated, then the LTF sequence value for each subcarrier of this one 26-tone DRU is 0; in other words, the signal carried on each subcarrier of this one 26-tone DRU is 0.

[0130] For example, the LTF can be generated based on the LTF sequence and the P matrix, or the LTF can be generated based on the LTF sequence and the R matrix. As an example, if the number of spatial streams used to send PPDUs is 1, then the aforementioned LTF can carry the LTF sequence value corresponding to the allocated DRU. As another example, if the number of spatial streams used to send PPDUs is greater than or equal to 2, then the aforementioned LTF can be determined based on the LTF sequence value corresponding to the allocated DRU, such as the LTF being determined based on the aforementioned LTF sequence value and the P matrix, or the LTF being determined based on the aforementioned LTF sequence value and the R matrix. Further explanations regarding LTF and LTF sequences can be found above and will not be detailed here.

[0131] In one possible implementation, the first station can determine the LTF based on the size and location of the assigned DRU.

[0132] 603. The second station performs channel estimation based on the predefined LTF sequence and LTF.

[0133] For details on the characteristics that the predefined LTF sequence must satisfy, please refer to step 601, which will not be elaborated here.

[0134] In this embodiment of the application, the LTF sequence can effectively reduce PAPR by satisfying the above characteristics.

[0135] The following describes the design principles of the LTF sequences involved in the embodiments of this application.

[0136] Taking N subcarriers in a discrete bandwidth as an example, for two subcarriers with an index difference of N / 2, their time-domain waveforms exhibit the following relationship: If the two subcarriers correspond to the same LTF sequence value, then for the time-domain waveforms of these two subcarriers, the values ​​corresponding to the 1st, 3rd, 5th, 7th, etc., odd-numbered samples (i.e., the values ​​after time-domain transformation of the LTF sequence value) are opposite, while the values ​​corresponding to the 2nd, 4th, 6th, 8th, etc., even-numbered samples are the same. In other words, if the two subcarriers correspond to opposite LTF sequence values, then for the time-domain waveforms of these two subcarriers, the values ​​corresponding to the 1st, 3rd, 5th, 7th, etc., odd-numbered samples are the same, while the values ​​corresponding to the 2nd, 4th, 6th, 8th, etc., even-numbered samples are opposite. For example, both of the above subcarriers are either data subcarriers or both are pilot subcarriers. The following examples illustrate this:

[0137] For example, in a 20MHz IFFT with 256 samples, the index difference between the subcarrier with index 13 and the subcarrier with index -115 is 128. When these two subcarriers correspond to the same LTF sequence value, the odd-numbered samples (1st, 3rd, 5th, 7th, etc.) of their time-domain waveforms have opposite values, while the even-numbered samples (2nd, 4th, 6th, 8th, etc.) have the same value. Similarly, in a 40MHz IFFT with 512 samples, the index difference between the subcarrier with index 14 and the subcarrier with index -242 is 256. When these two subcarriers correspond to the same LTF sequence value, the odd-numbered samples (1st, 3rd, 5th, 7th, etc.) of their time-domain waveforms have opposite values, while the even-numbered samples (2nd, 4th, 6th, 8th, etc.) have the same value. For example, in an IFFT with 1024 samples for 80MHz, the index difference between the subcarrier with index 270 and the subcarrier with index -242 is 512. When these two subcarriers correspond to the same LTF sequence values, the odd-numbered samples (1st, 3rd, 5th, 7th, etc.) of their time-domain waveforms have opposite values, while the even-numbered samples (2nd, 4th, 6th, 8th, etc.) of their time-domain waveforms have the same value.

[0138] Taking Tables 1-5 as examples, for any 26-tone DRU (26 subcarriers) in a 20MHz subcarrier plan, or for a 26-tone DRU (26 subcarriers) that can be merged into a larger DRU, the index difference between the i-th subcarrier with an index greater than 0 and the i-th subcarrier with an index less than 0 is 126 or 117, close to 128. For any 26-tone DRU (26 subcarriers) in a 40MHz subcarrier plan, or for a 26-tone DRU (26 subcarriers) that can be merged into a larger DRU, the index difference between the i-th subcarrier with an index greater than 0 and the i-th subcarrier with an index less than 0 is 252, close to 256. For any 52-tone DRU in an 80MHz subcarrier plan, the index difference between the i-th subcarrier with an index greater than 0 among the odd-numbered subcarriers (out of 26 subcarriers) and the i-th subcarrier with an index less than 0 among the odd-numbered subcarriers is 500, close to 512. Alternatively, for any 52-tone DRU in an 80MHz subcarrier plan, the index difference between the i-th subcarrier with an index greater than 0 among the even-numbered subcarriers (out of 26 subcarriers) and the i-th subcarrier with an index less than 0 among the even-numbered subcarriers is 500, close to 512. Of course, the index difference shown here is based on Tables 1-5; as the subcarrier indices of the DRU change, the index difference between the two subcarriers can also change. Even with a changing index difference, the LTF sequence can still satisfy the characteristics shown in Implementation 1 or Implementation 2 above.

[0139] Therefore, for the aforementioned 26 subcarriers, the i-th subcarrier among those with an index less than 0 and the i-th subcarrier among those with an index greater than 0 can be considered as a pair of subcarriers, resulting in a total of 13 pairs of subcarriers. Each pair of subcarriers in 6 pairs can correspond to the same LTF sequence value, and each pair of subcarriers in 7 pairs can correspond to opposite LTF sequence values. Alternatively, each pair of subcarriers in 6 pairs can correspond to opposite LTF sequence values, and each pair of subcarriers in 7 pairs can correspond to the same LTF sequence value.

[0140] The time-domain waveforms of the aforementioned 26 subcarriers are a superposition of the time-domain waveforms of each of their constituent subcarriers. For a pair of subcarriers corresponding to the same LTF sequence value, the energy of their time-domain waveforms is mainly concentrated on even-numbered samples. For a pair of subcarriers corresponding to opposite LTF sequence values, the energy of their time-domain waveforms is mainly concentrated on odd-numbered samples. Among the 13 pairs of subcarriers, the number of subcarrier pairs corresponding to the same LTF sequence value and the number of subcarrier pairs corresponding to opposite LTF sequence values ​​are close, thus making the energy carried by odd-numbered samples and even-numbered samples in the time-domain waveforms of the aforementioned 26 subcarriers close, resulting in a lower PAPR for the time-domain waveforms of these 26 subcarriers. Since a larger-sized DRU can be obtained by combining the aforementioned 26 subcarriers, the energy carried by odd-numbered samples and even-numbered samples in a larger-sized DRU are also close, resulting in a lower PAPR for its time-domain waveform.

[0141] The following describes the LTF sequence search method involved in the embodiments of this application.

[0142] The LTF sequences obtained based on the features satisfied by the LTF sequences shown in the embodiments of this application, and the search methods described below, are all within the protection scope of the embodiments of this application.

[0143] The 20MHz band includes nine 26-tone DRUs. For each 26-tone DRU, or a 26-tone DRU that can be combined into a larger DRU, according to... or Generate sequences of length 13 (e.g., X sequences) corresponding to subcarriers with indices less than 0, and sequences of length 13 (e.g., Y sequences) corresponding to subcarriers with indices greater than 0. Concatenate the X and Y sequences to obtain Z sequences. From these Z sequences, select W sequences with lower PAPR. For example, assuming the DRU supports a maximum of 4 spatial streams, for a sequence, calculate the PAPR corresponding to each spatial stream, and use the highest PAPR as the PAPR of that sequence, thus filtering out W sequences with lower PAPR from the Z sequences. The PAPR value is related to the DRU's data subcarrier index and pilot subcarrier index. For example, LTF sequences can be designed using the data subcarriers and pilot subcarriers shown in Tables 1-5 above.

[0144] Since a 52-tone DRU can be obtained by merging two 26-tone DRUs, the sequence corresponding to a 52-tone DRU can also be formed by splicing the sequences corresponding to two 26-tone DRUs, or by performing a -1 phase rotation on the entire sequence corresponding to two 26-tone DRUs. From the spliced ​​sequences, the K sequences with the lowest PAPR are selected, as described above. For example, if 52-tone DRU1 is formed by merging 26-tone DRU1 and 26-tone DRU2, then the sequence corresponding to 52-tone DRU1 = [a * (the sequence corresponding to 26-tone DRU1) * (the sequence corresponding to 26-tone DRU2)], where a = 1 or -1, b = 1 or -1. All sequences corresponding to 52-tone DRUs can be spliced ​​in the same way.

[0145] Since a 106-tone DRU consists of two 52-tone DRUs and two single subcarriers, the sequence corresponding to the 106-tone DRU can also be formed by concatenating the sequences corresponding to the two 52-tone DRUs and the possible values ​​(e.g., four possible values) of the other two subcarriers, or by concatenating the sequences corresponding to the two 52-tone DRUs after performing a -1 phase rotation and the possible values ​​(e.g., four possible values) of the other two subcarriers. The Q sequences with lower PAPR are selected from the concatenated sequences, as described above. For example, 106-tone DRU 1 is formed by merging 52-tone DRU 1 and 52-tone DRU 2. The sequence corresponding to 106-tone DRU 1 is [a * (the sequence corresponding to 52-tone DRU 1) b * (the sequence corresponding to 52-tone DRU 2) cd], where a = 1 or -1, b = 1 or -1, c = 1 or -1, and d = 1 or -1. The sequences corresponding to 106-tone DRU are all obtained by splicing them together in the same way.

[0146] Therefore, the LTF sequence corresponding to 20MHz can be determined by the LTF sequences corresponding to the two 106-tone DRUs and the sequence corresponding to the 26-tone DRU 5.

[0147] The above search method is illustrated using 20MHz as an example. The LTF sequence corresponding to 40MHz or 80MHz can also be obtained through a similar search method, which will not be described in detail here.

[0148] The following describes the LTF sequence provided in this application embodiment when the discrete bandwidth is 20MHz. The inverted sequences of the LTF sequences shown below are also within the protection scope of this application embodiment. Each sequence shown below is an LTF sequence, or an LTF sequence is the inverted sequence of each sequence shown below. This application embodiment does not limit this.

[0149] Taking a subcarrier spacing of 78.125KHz as an example, there are 256 subcarriers within 20MHz, and their index range is [-128:127].

[0150] As one possible implementation, the LTF sequence is 256 units long, meaning it consists of 256 LTF sequence values, each corresponding to one of the 256 subcarriers. The guard subcarrier and the DC subcarrier within these 256 subcarriers have an LTF sequence value of 0. The LTF sequence is represented as LTF. -128:127 Or DRU LTF -128:127 .

[0151] As another possible implementation, the LTF sequence has a length of 241, meaning it consists of 241 LTF sequence values, each corresponding to one of 241 subcarriers. These 241 subcarriers are the 256 subcarriers mentioned above, excluding the guard subcarrier. The LTF sequence is represented as LTF. -120:120 Or DRU LTF -120:120 Of course, the length of an LTF sequence can also be greater than 240 and less than 256. The expressions for LTF sequences will not be listed one by one.

[0152] As an example 1, the LTF sequence is:

[0153] LTF -128:127=[0,0,0,0,0,0,0,0,-1,-1,1,-1,1,1,-1,-1,-1,-1,1,1,-1,1,1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1,1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 ,1,-1,1,1,-1,1,1,1,-1,1,-1,1,1,1,1,1,-1,1,-1,-1,-1,1,-1,1,-1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,1,1,1,1,-1,-1,-1,-1,1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,-1,1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,1, 1,0,0,0,-1,1,1,-1,1,1,-1,1,-1,1,1,1,-1,1,1,-1,-1,-1,1,1,-1,1,1,1,-1,1,1,-1,1,1,-1,-1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,-1,1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1, -1,1,1,1,1,1,- ...

[0154] Or, LTF -120:120=[-1,-1,1,-1,1,1,-1,-1,-1,1,1,-1,-1,1,1,-1,1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,-1,-1,-1,1,-1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1, 1,-1,1,1,1,-1,1,-1,1,1,1,1,1,1,-1,1,-1,-1,-1,1,-1,1,-1,-1,-1,-1,-1,-1,-1,1,1,1,1,1,-1,-1,-1,-1,1,1,1,1,-1,-1,1,1,1,-1,1,-1,1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,1 ,0,0,0,-1,1,1,-1,1,1,-1,1,-1,-1,1,1,1,-1,1,-1,-1,-1,1,1,-1,1,1,1,1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,1,1,-1,-1,1,1,-1,-1, 1,1,-1,-1,1,1,1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,-1,1,1,-1,1,1,-1,-1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,1,-1,1,1,1,1,-1,-1,-1,1,-1,1,-1,1,1,-1,1,1,1,-1,1,1,1,-1,1,-1,-1,-1,-1).

[0155] Or, LTF -128:127 =

[0156] The sequence obtained by inverting the above sequence also falls within the protection scope of this application's embodiments. The inverted sequence shown in Example 1 is as follows:

[0157] LTF -128:127=[0,0,0,0,0,0,0,0,1,1,-1,1,-1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,-1,1,-1,1,1,1,1,1,-1,1,1,1,1,-1,1,1,1,1,-1,1,1,1,-1,1,1,1,-1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1 ,-1 ... ,1,-1,-1,1,-1,-1,1,-1,1,1,-1,-1,-1,1,-1,-1,1,1,1,1,1,-1,-1,1,-1,-1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,1,-1,-1,-1,1,1,1,-1,1,1,1,-1,1,1,1,1,-1,-1,1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1, -1,-1,-1,1,1,- ...

[0158] The above expression is just an example; for LTF... -120:120 The expressions are not detailed here.

[0159] As another example 2, the LTF sequence is:

[0160] LTF -128:127=[0,0,0,0,0,0,0,0,-1 ... -1,1,-1,1,1,-1,1,1,-1,-1,-1,-1,-1,1,-1,1,-1,-1,-1,-1,-1,-1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1,1,-1,-1,-1,-1,-1,1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,- 1,1,0,0,0,-1,-1,1,-1,1,1,-1,-1,-1,1,1,1,1,-1,-1,-1,1,1,1,-1,1,1,1,-1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,-1,1,1,-1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,-1,1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,- 1,1,1,1,1,1,- ...

[0161] Or, LTF -120:120=[-1, ... ,1,-1,1,1,1,-1,-1,-1,-1,1,-1,1,-1,1,-1,-1,-1,1,-1,1,-1,1,-1,1,1,1,-1,1,1,-1,1,1,-1,1,-1,1,1,1,1,-1,-1,-1,-1,1,1,1,1,1,-1,-1,-1,-1,-1,-1 ,1,0,0,0,-1,-1,1,-1,1,1,-1,1,-1,-1,1,1,1,1,-1,-1,-1,1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,-1,-1,-1,1,-1,-1,1,-1,-1,1,-1,-1,1,-1,-1,1,-1,-1,1,-1,-1,1,-1,-1,1, 1,-1,-1,1,1,1,1,1,-1,1,1,-1,1,1,1,-1,-1,1,1,1,-1,-1,-1,-1,-1,-1,-1,-1,1,1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1).

[0162] Or, LTF -128:127 =

[0163] Taking four spatial flows as an example, calculate the PAPR corresponding to the four spatial flows; one LTF sequence corresponds to four spatial flows, each with four PAPRs. The largest PAPR among these four PAPRs is called the maximum PAPR of the LTF sequence.

[0164] The LTF sequences shown in Example 1 and Example 2 have the same PAPR. The PAPR in Table 6 is the maximum PAPR of the LTF sequence shown in Example 1, or the maximum PAPR of the LTF sequence shown in Example 2.

[0165] Table 6

[0166] There is an LTF sequence in the prior art, as shown in Table 7. Table 7 shows the LTF sequence corresponding to the subcarrier with index -122:122.

[0167] Table 7

[0168] Table 8 shows the PAPR for the LTF sequences shown in Table 7, as illustrated in Table 8:

[0169] Table 8

[0170] The difference between PAPR shown in Table 6 and Table 8 is shown in Table 9:

[0171] Table 9

[0172] For 26-tone DRU, the nine PAPRs shown in Table 6, in ascending order, are as follows:

[0173] 2.9600 3.4572 3.4903 3.5685 3.5887 3.5998 3.6803 3.7064 3.7558

[0174] For 26-tone DRU, the nine PAPRs shown in Table 8 are in ascending order as follows:

[0175] 2.9600 3.4200 3.4700 3.5600 3.6700 3.7000 3.7700 3.7900 3.8000

[0176] As can be seen, the five PAPRs corresponding to the LTF sequence shown in the embodiments of this application (i.e., 3.5887 3.5998 3.6803 3.7064 3.7558) are successively smaller than the five PAPRs corresponding to the LTF sequence shown in Table 7 (i.e., 3.6700 3.7000 3.7700 3.7900 3.8000).

[0177] For 52-tone DRU and 106-tone DRU, the PAPR of the LTF sequence shown in the embodiments of this application is lower than that of the LTF sequence shown in Table 7, and the amplitude is between 0.2dB and 0.3dB.

[0178] Therefore, the LTF sequence provided in this application embodiment can further reduce PAPR on each DRU.

[0179] As yet another example 3, the LTF sequence is:

[0180] LTF-128:127 =[0,0,0,0,0,0,0,0,-1,-1,1,-1,1,-1,-1,-1,-1,1,1,-1,-1,1,-1,1,-1,-1,1,-1,-1,-1,-1,1,-1,-1,-1,1,-1,-1,1,-1,1,-1,-1,-1,-1,-1,-1,1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,1,-1,1,1,1,-1,1,1,1,1,1,-1, -1,1,1,1,-1,-1,-1,1,-1,-1,1,-1,1,1,1,1,-1,1,-1,-1,-1,1,1,1,1,-1,1,-1,-1,-1,-1,-1,1,1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,-1,1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 ,1,1,0,0,0,1,1,1,-1,1,1,-1,1,1,1,1,-1,-1,-1,1,1,1,-1,-1,1,-1,-1,1,1,1,-1,1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,1,-1,1,1, 1,1,-1,1,1,-1,1,-1,-1,-1,1,1,1,-1,1,-1,1,1,-1,1,1,-1,1,1,1,-1,-1,1,1,1,1,-1,1,1,1,1,1,-1,1,1,1,1,1,-1,1,1,1,1,-1,1,1,1,1,-1,1,1,1,-1,1,1,1,-1,0,0,0,0,0,0,0,0).

[0181] Or, LTF -120:120=[-1,-1,1,-1,1,-1,-1,-1,-1,1,1,-1,-1,1,1,-1,1,-1,-1,1,-1,-1,-1,1,-1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,1,-1,-1,1,-1,-1,-1,-1,1,-1,-1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,-1,1,1,1,-1,-1,1,1,1,1 ,-1,-1,-1,1,-1,-1,1,-1,1,1,1,1,1,- ... 1,1,0,0,0,1,1,1,-1,1,1,-1,1,1,-1,1,1,-1,-1,1,1,-1,-1,1,-1,-1,1,1,-1,1,1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,1,1,-1,-1,1, 1,-1,1,1,1,-1,1,1,-1,1,-1,-1,-1,1,1,-1,1,-1,1,1,-1,1,1,-1,1,1,-1,-1,1,1,1,1,-1,1,1,1,1,-1,1,1,1,1,1,-1,1,1,1,1,-1,1,1,1,-1,1,1,1,-1,1,1,1,1,-1,1,1,1,-1,1,1,1,-1,1,1,-1,1,1,-1).

[0182] Or, LTF -128:127 =

[0183] As another example 4, the LTF sequence is:

[0184] LTF -128:127=[0,0,0,0,0,0,0,0,-1 ... 1,-1,1,1,1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1,-1,-1,-1,-1,-1,1,1,1,1,1,1,1,1,1,1,-1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,1,1,1,-1,-1,-1,-1,-1,-1,1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,- 1,-1,1,0,0,0,1,-1,1,-1,1,1,-1,1,1,-1,1,1,-1,-1,1,1,1,-1,1,-1,1,1,-1,1,1,-1,1,1,-1,-1,-1,1,1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,1,-1,-1,1,1 ,1,-1,1,1,-1,1,-1,-1,1,1,1,1,1,1,1,-1,1,1,1,-1,1,1,1,-1,-1,-1,-1,1,1,1,1,-1,1,1,1,1,-1,1,1,1,1,1,-1,1,1,1,1,-1,1,1,1,1,-1,0,0,0,0,0,0,0,0).

[0185] Or, LTF -120:120=[-1,-1,1,-1,1,-1,-1,-1,-1,-1,1,1,-1,-1,1,1,-1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,1,-1,1,-1,1,1,-1,1,1,-1,-1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,-1,1,1, 1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1,-1,1,-1,-1,-1,-1,1,1,1,1,1,1,1,1,1,-1,1,-1,-1,-1,1,1,1,-1,-1,-1,-1,-1,-1,1,1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1 ,-1,1,0,0,0,1,-1,1,-1,1,1,-1,1,-1,1,1,-1,1,1,-1,-1,1,1,1,-1,1,-1,1,1,-1,1,1,-1,-1,-1,1,1,-1,-1,1,1,-1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,1,1,-1, -1,1,1,1,-1,1,1,-1,1,-1,1,-1,1,1,-1,1,1,1,-1,1,1,-1,1,1,-1,-1,-1,1,-1,1,-1,1,1,-1,1,1,1,-1,1,1,1,-1,1,1,-1,1,1,-1,-1,-1,-1,-1,-1,1,1,1,-1,1,1,-1,1,-1,1,-1,1,-1,1,-1.

[0186] Or, LTF -128:127 =

[0187] Taking four spatial flows as an example, calculate the PAPR corresponding to the four spatial flows; one LTF sequence corresponds to four spatial flows, each with four PAPRs. The largest PAPR among these four PAPRs is called the maximum PAPR of the LTF sequence.

[0188] The LTF sequences shown in Examples 3 and 4 have the same PAPR. The PAPR in Table 10 is the maximum PAPR of the LTF sequence shown in Example 3, or the maximum PAPR of the LTF sequence shown in Example 4.

[0189] Table 10

[0190] The difference between PAPR shown in Table 10 and Table 8 is shown in Table 11:

[0191] Table 11

[0192] For 26-tone DRU, the nine PAPRs shown in Table 10, in ascending order, are as follows:

[0193] 2.9700 3.3306 3.4572 3.5053 3.5887 3.6181 3.6507 3.7064 3.7558

[0194] As can be seen from this, the eight PAPRs corresponding to the LTF sequence shown in the embodiments of this application (i.e., 3.3306 3.4572 3.5053 3.5887 3.6181 3.6507 3.7064 3.7558) are successively smaller than the eight PAPRs corresponding to the LTF sequence shown in Table 7 (i.e., 3.4200 3.4700 3.5600 3.6700 3.7000 3.7700 3.7900 3.8000).

[0195] For 52-tone DRU and 106-tone DRU, the PAPR of the LTF sequence shown in the embodiments of this application is lower than that of the LTF sequence shown in Table 7, and the amplitude is between 0.1dB and 0.5dB.

[0196] Therefore, the LTF sequence provided in this application embodiment can further reduce PAPR on each DRU.

[0197] This application also provides a communication method, the method comprising:

[0198] S1. The first station determines the LTF sequence, which is described above, such as in Examples 1 to 4, and will not be detailed here.

[0199] The first station determines the LTF sequence, including: the first station determines the LTF sequence based on discrete bandwidth and sequence pattern, wherein the sequence pattern includes 1x LTF sequence pattern, 2x LTF sequence pattern or 4x LTF sequence pattern.

[0200] Optionally, for a DRU, the LTF sequence can only have a 4x LTF sequence mode, so that when the first station learns that the RU it is using is a DRU, it can determine the LTF sequence only based on the discrete bandwidth of the DRU.

[0201] S2. The first station sends a PPDU, which includes an LTF. The LTF is determined based on the LTF sequence value corresponding to the assigned DRU.

[0202] As you can understand, the details of this method can be found in similar details above, and will not be elaborated here.

[0203] This application also provides a communication method, the method comprising:

[0204] The second site receives the PPDU, which includes the LTF;

[0205] The second station performs channel estimation based on a predefined LTF sequence and LTF. The predefined LTF sequence is described above, such as in Examples 1 to 4, and will not be detailed here.

[0206] As you can understand, the details of this method can be found in similar details above, and will not be elaborated here.

[0207] The following describes the communication device provided in the embodiments of this application.

[0208] This application divides the communication device into functional modules according to the above method embodiments. For example, each function can be divided into its own functional modules, or two or more functions can be integrated into one processing module. The integrated modules can be implemented in hardware or as software functional modules. It should be noted that the module division in this application is illustrative and only represents one logical functional division; other division methods may be used in actual implementation. The communication device of the embodiments of this application will be described in detail below with reference to Figures 7 to 9.

[0209] Figure 7 is a schematic diagram of a communication device provided in an embodiment of this application. As shown in Figure 7, the communication device includes a processing module 701 and a transceiver module 702. The transceiver module 702 can implement corresponding communication functions, and the processing module 701 is used to implement corresponding processing functions. For example, the transceiver module 702 can also be called an interface, a communication interface, or a communication module, etc.

[0210] In some embodiments of this application, the communication device can be used to perform the actions performed by the first station in the above method embodiments. In this case, the first station can be the device itself or a chip or functional module configurable in the device. The transceiver module 702 is used to perform the transceiver-related operations of the first station in the above method embodiments, and the processing module 701 is used to perform the processing-related operations of the first station in the above method embodiments.

[0211] Processing module 701 can be used to determine the LTF sequence and generate PPDUs based on the assigned DRUs. For example, processing module 701 can generate PPDUs based on the size and location of the assigned DRUs.

[0212] The transceiver module 702 can be used to send or output the PPDU.

[0213] For example, the transceiver module 702 can also be used to receive or input trigger frames.

[0214] Reusing Figure 7, in some other embodiments of this application, the communication device can be used to perform the actions performed by the second station in the above method embodiments. In this case, the second station can be the device itself or a chip or functional module configurable in the device. The transceiver module 702 is used to perform the transceiver-related operations of the second station in the above method embodiments, and the processing module 701 is used to perform the processing-related operations of the second station in the above method embodiments.

[0215] The transceiver module 702 can be used to receive a PPDU, which includes an LTF.

[0216] The processing module 701 can be used to perform channel estimation based on a predefined LTF sequence and LTF.

[0217] For example, the transceiver module 702 can also be used to send or output trigger frames.

[0218] For example, the transceiver module 702 described above can be an antenna module. Alternatively, the transceiver module 702 can be an input / output module. Optionally, in the above embodiments, the communication device may further include a storage module, which can be used to store instructions and / or data. The processing module 701 can read the instructions and / or data from the storage module to enable the communication device to implement the aforementioned method embodiments.

[0219] For details regarding the specific explanations of each term, noun, or step in the above embodiments, please refer to the descriptions in the above method embodiments; they will not be detailed here.

[0220] The specific descriptions of the transceiver module and processing module shown in the above embodiments are merely examples. For the specific functions or execution steps of the transceiver module and processing module, please refer to the above method embodiments, which will not be described in detail here.

[0221] It is understandable that the module division in the above-mentioned device is merely a logical functional division. Each function can correspond to a functional module, or two or more functions can be integrated into one functional module. In actual implementation, all or some modules can be integrated into one physical entity, or they can be distributed across different physical entities. Furthermore, the above-mentioned functional modules can be implemented in hardware, software, or a combination of both.

[0222] In one example, the functional unit in any of the above devices may be one or more integrated circuits configured to implement the above methods, such as: one or more application-specific integrated circuits (ASICs), or one or more central processing units (CPUs), one or more microcontroller units (MCUs), one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms.

[0223] The communication device according to the embodiments of this application has been described above. The following describes possible product forms of the communication device. Any product possessing the functions of the communication device described in FIG. 7 above falls within the protection scope of the embodiments of this application. The following description is merely illustrative and does not limit the product form of the communication device according to the embodiments of this application to this extent.

[0224] In one possible implementation, in the communication device shown in FIG7, the processing module 701 can be one or more processors, and the transceiver module 702 can be a transceiver, or the transceiver module 702 can also be a transmitting module and a receiving module. The transmitting module can be a transmitter, and the receiving module can be a receiver. The transmitting module and the receiving module are integrated into one device, such as a transceiver. In the embodiments of this application, the processor and the transceiver can be coupled, etc., and the connection method of the processor and the transceiver is not limited in the embodiments of this application. In the process of executing the above method, the process of sending information in the above method can be the process of the processor outputting the above information. When outputting the above information, the processor outputs the above information to the transceiver so that the transceiver can transmit it. After the above information is output by the processor, it may need to undergo other processing before reaching the transceiver. Similarly, the process of receiving information in the above method can be the process of the processor receiving the input above information. When the processor receives the input information, the transceiver receives the above information and inputs it into the processor. Furthermore, after the transceiver receives the above information, the above information may need to undergo other processing before being input into the processor.

[0225] Figure 8 is a schematic diagram of another structure of the communication device provided in an embodiment of this application. As shown in Figure 8, the communication device 80 includes one or more processors 820 and transceivers 810.

[0226] In some embodiments of this application, the communication device can be used to execute the steps, methods, or functions performed by the first station. For example, the processor 820 can be used to execute the functions or steps implemented by the processing module 701 shown in FIG. 7, and the transceiver 810 can be used to execute the functions or steps implemented by the transceiver module 702 shown in FIG. 7. Detailed descriptions of the processor 820 and the transceiver 810 can be found in FIG. 7 or the method embodiments shown above, and will not be elaborated further here.

[0227] In other embodiments of this application, the communication device is used to execute the steps, methods, or functions performed by the second station. For example, the processor 820 can be used to execute the functions or steps implemented by the processing module 701 shown in FIG. 7, and the transceiver 810 can be used to execute the functions or steps implemented by the transceiver module 702 shown in FIG. 7. Detailed descriptions of the processor 820 and the transceiver 810 can be found in FIG. 7 or the method embodiments shown above, and will not be elaborated further here.

[0228] In various implementations of the communication device shown in Figure 8, the transceiver may include a receiver for performing a receiving function (or operation) and a transmitter for performing a transmitting function (or operation). The transceiver is also used to communicate with other devices / appliances via a transmission medium.

[0229] Optionally, the communication device 80 may further include one or more memories 830 for storing program instructions and / or data. The memory 830 is coupled to the processor 820. The coupling in this embodiment is an indirect coupling or communication connection between communication devices, units, or modules, and can be electrical, mechanical, or other forms, used for information exchange between the communication devices, units, or modules. The processor 820 may operate in conjunction with the memory 830. The processor 820 may execute program instructions stored in the memory 830. Optionally, at least one of the above-mentioned memories may be included in the processor.

[0230] This application embodiment does not limit the specific connection medium between the transceiver 810, processor 820, and memory 830. In this application embodiment, the memory 830, processor 820, and transceiver 810 are connected via a bus 840 in Figure 8. The bus is represented by a thick line in Figure 8. The connection methods between other components are only for illustrative purposes and are not intended to be limiting. The bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used in Figure 8, but this does not mean that there is only one bus or one type of bus.

[0231] In the embodiments of this application, the processor may be a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., and can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or being executed by a combination of hardware and software modules within the processor.

[0232] In this application embodiment, the memory may include, but is not limited to, non-volatile memory such as hard disk drive (HDD) or solid-state drive (SSD), random access memory (RAM), erasable programmable read-only memory (EPROM), read-only memory (ROM), or compact disc read-only memory (CD-ROM), etc. Memory is any storage medium capable of carrying or storing program code having instruction or data structure forms, and capable of being read and / or written by a computer (such as the communication device shown in this application), but is not limited to this. The memory in this application embodiment may also be a circuit or any other device capable of implementing storage functions, used to store program instructions and / or data.

[0233] The processor 820 is primarily used for processing communication protocols and data, controlling the entire communication device, executing software programs, and processing software program data. The memory 830 is primarily used for storing software programs and data. The transceiver 810 may include control circuitry and an antenna. The control circuitry is primarily used for converting baseband signals to radio frequency signals and processing radio frequency signals. The antenna is primarily used for transmitting and receiving radio frequency signals in the form of electromagnetic waves. Input / output devices, such as touchscreens, displays, and keyboards, are primarily used for receiving user input data and outputting data to the user.

[0234] When the communication device is powered on, the processor 820 can read the software program in the memory 830, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be transmitted wirelessly, the processor 820 performs baseband processing on the data to be transmitted and outputs the baseband signal to the radio frequency (RF) circuit. The RF circuit processes the baseband signal and transmits the RF signal outward in the form of electromagnetic waves through the antenna. When data is sent to the communication device, the RF circuit receives the RF signal through the antenna, converts the RF signal into a baseband signal, and outputs the baseband signal to the processor 820. The processor 820 converts the baseband signal into data and processes the data.

[0235] In another implementation, the radio frequency circuitry and antenna can be set up independently of the processor performing baseband processing. For example, in a distributed scenario, the radio frequency circuitry and antenna can be arranged remotely, independent of the communication device.

[0236] The communication device shown in this application embodiment may have more components than those in Figure 8, and this application embodiment does not limit this. The methods executed by the processor and transceiver shown above are only examples, and the specific steps executed by the processor and transceiver can be referred to the methods described above. The dashed lines in Figure 8 indicate optional parts.

[0237] In another possible implementation, in the communication device shown in Figure 7, the processing module 701 can be one or more logic circuits, and the transceiver module 702 can be an input / output interface, or a communication interface, or an interface circuit, or an interface, etc. Alternatively, the transceiver module 702 can also be a sending module and a receiving module, where the sending module can be an output interface and the receiving module can be an input interface, and the sending module and receiving module are integrated into one module, such as an input / output interface.

[0238] Figure 9 is a schematic diagram of another structure of the communication device provided in an embodiment of this application. As shown in Figure 9, the communication device includes a logic circuit 901 and an interface 902. That is, the processing module 701 can be implemented using the logic circuit 901, and the transceiver module 702 can be implemented using the interface 902. The logic circuit 901 can be a chip, processing circuit, integrated circuit, or system-on-chip (SoC) chip, etc., and the interface 902 can be a communication interface, input / output interface, pins, etc. For example, Figure 9 illustrates the communication device as a chip, which includes the logic circuit 901 and the interface 902.

[0239] In this embodiment, the logic circuit and the interface can also be coupled to each other. The specific connection method of the logic circuit and the interface is not limited in this embodiment. For example, the logic circuit 901 can be used to execute the functions or steps implemented by the processing module 701 shown in FIG. 7, and the interface 902 can be used to execute the functions or steps implemented by the transceiver module 702 shown in FIG. 7. For a detailed description of the logic circuit 901 and the interface 902, please refer to FIG. 7 or the method embodiment shown above, which will not be detailed here.

[0240] The communication device shown in the embodiments of this application can implement the method provided in the embodiments of this application in hardware form, or it can implement the method provided in the embodiments of this application in software form, etc., and the embodiments of this application do not limit it in this way.

[0241] Furthermore, embodiments of this application also provide a communication system, which includes a first station and a second station, the first station and the second station being used to perform the methods in any of the foregoing embodiments.

[0242] This application also provides a computer program for implementing the operations and / or processes performed by various sites in the methods provided in this application.

[0243] This application also provides a computer-readable storage medium storing computer code that, when executed on a computer, causes the computer to perform the operations and / or processes performed by various communication devices in the methods provided in this application.

[0244] This application also provides a computer program product comprising computer code or a computer program that, when run on a computer, causes the operations and / or processes performed by various entities in the method provided in this application to be executed.

[0245] In the embodiments provided in this application, it should be understood that the disclosed systems, communication devices, and methods can be implemented in other ways. For example, the communication device embodiments described above are merely illustrative. For instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, communication devices, or modules, or it may be an electrical, mechanical, or other form of connection.

[0246] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the technical effects of the solutions provided in the embodiments of this application.

[0247] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0248] If the integrated module is implemented as a software functional module and sold or used as an independent product, it 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 all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a readable 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 readable 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.

Claims

1. A communication method characterized by comprising: The method comprises: The first station determines a long training field (LTF) sequence that satisfies: the LTF sequence value corresponding to the 26-tone DRU satisfies or or or a i is the LTF sequence value corresponding to the i-th subcarrier with index less than 0 in the 26-tone DRU, b i is the LTF sequence value corresponding to the i-th subcarrier with index greater than 0 in the 26-tone DRU; The first station sends a physical layer protocol data unit (PPDU), the PPDU comprising a long training field (LTF) determined according to a LTF sequence value corresponding to an allocated discrete resource unit (DRU).

2. The method of claim 1, wherein, The LTF is also determined according to a LTF sequence value corresponding to an unallocated DRU, the LTF sequence value corresponding to the unallocated DRU being 0.

3. The method according to claim 1 or 2, characterized in that, The discrete bandwidth of the DRU is 20MHz, and a difference between an index of an ith subcarrier with an index greater than 0 and an index of an ith subcarrier with an index less than 0 is 126 or 117; or The discrete bandwidth of the DRU is 40MHz, and a difference between an index of an ith subcarrier with an index greater than 0 and an index of an ith subcarrier with an index less than 0 is 252.

4. The method according to any one of claims 1 to 3, characterized in that, The discrete bandwidth of the DRU is 20 MHz, and the LTF sequence is any one of the following: LTF -128:127 = {0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, 1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, 1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, 0, 0, 0, 0, 0, 0, 0}; LTF -128:127 = {0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 0, 0, 0, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, 0, 0, 0, 0, 0, 0, 0}; LTF -128:127 = {0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, 0, 0, 0, 0, 0, 0, 0}; or, LTF -128:127 ＝ {0,0,0,0,0,0,0,0,-1,-1,1,-1,1,-1,-1,-1,-1,-1,1,1,-1,-1,1,1,1,-1,1,-1,-1,1,-1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,1,-1,-1,- 1,-1,-1,-1,-1,-1,1,-1,1,1,-1,1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1,-1,1,-1,1,-1,-1,-1,1,1,1,1,1,1,1,1,1,1,-1,1,-1,1,1,1,1,1,-1,-1,1,-1,1,1,1,-1,-1,-1,-1,-1,1,-1,1,1,1,-1,-1,-1,-1,1,-1,-1,1,0,0,0,1,-1,1,-1,1,1,-1,1,-1,1,1,-1,1,1,-1,-1,1,1,1,1,-1,1,-1,-1,1,1,-1,1,1,-1,-1,-1,1,1,-1,1,1,-1,-1,1,-1,-1,-1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,1,-1,1,1,-1,1,-1,-1,1,1,-1,1,1,1,1,1,-1,1,1,-1,1,1,1,-1,-1,1,-1,1,-1,1,1,1,-1,1,1,1,1,1,1,-1,1,1,1,-1,-1,-1,-1,1,-1,-1,-1,-1,1,1,1,1,-1,1,1,-1,0,0,0,0,0,0,0}； Wherein, -128:127 represents a subcarrier index range of 20MHz.

5. A communication method characterized by comprising: The method comprises: A second station receives a physical layer protocol data unit (PPDU), the PPDU comprising a long training field (LTF); The second station performs channel estimation according to the predefined LTF sequence and the LTF, the predefined LTF sequence satisfying: the LTF sequence value corresponding to the 26-tone DRU satisfies or or or a i is the LTF sequence value corresponding to the i-th subcarrier with index less than 0 in the 26-tone DRU, and i is the LTF sequence value corresponding to the i-th subcarrier with index greater than 0 in the 26-tone DRU.

6. The method of claim 5, wherein, The discrete bandwidth of an allocated discrete resource unit (DRU) is 20MHz, and a difference between an index of an ith subcarrier with an index greater than 0 and an index of an ith subcarrier with an index less than 0 is 126 or 117; or The discrete bandwidth of the allocated DRU is 40MHz, and a difference between an index of an ith subcarrier with an index greater than 0 and an index of an ith subcarrier with an index less than 0 is 252.

7. The method according to claim 5 or 6, characterized in that, The discrete bandwidth is 20 MHz, and the predefined LTF sequence is any one of the following: LTF -128:127 = {0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, -1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, -1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 0, 0, 0, -1, 1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, 1, -1, -1, 1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, 0, 0, 0, 0, 0, 0, 0}; LTF -128:127 = {0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 0, 0, 0, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, 1, -1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, 0, 0, 0, 0, 0, 0, 0}; LTF -128:127 = {0, 0, 0, 0, 0, 0, 0, 0, -1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, 1, 1, 1, -1, -1, -1, 1, -1, -1, 1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, -1, -1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, 1, -1, 1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, -1, -1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, -1, 1, -1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, 1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, 1, -1, 0, 0, 0, 0, 0, 0, 0}; or, LTF -128:127 ＝ {0,0,0,0,0,0,0,0,-1,-1,1,-1,1,-1,-1,-1,-1,-1,1,1,-1,-1,1,1,1,-1,1,-1,-1,1,-1,1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,1,-1,-1,- 1,-1,-1,-1,-1,-1,1,-1,1,1,-1,1,1,1,-1,-1,-1,1,1,1,-1,-1,-1,1,-1,-1,-1,-1,-1,1,-1,1,-1,1,-1,1,-1,-1,-1,1,1,1,1,1,1,1,1,1,1,-1,1,-1,1,1,1,1,1,-1,-1,1,-1,1,1,1,-1,-1,-1,-1,-1,1,-1,1,1,1,-1,-1,-1,-1,1,-1,-1,1,0,0,0,1,-1,1,-1,1,1,-1,1,-1,1,1,-1,1,1,-1,-1,1,1,1,1,-1,1,-1,-1,1,1,-1,1,1,-1,-1,-1,1,1,-1,1,1,-1,-1,1,-1,-1,-1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,1,-1,1,1,-1,1,-1,-1,1,1,-1,1,1,1,1,1,-1,1,1,-1,1,1,1,-1,-1,1,-1,1,-1,1,1,1,-1,1,1,1,1,1,1,-1,1,1,1,-1,-1,-1,-1,1,-1,-1,-1,-1,1,1,1,1,-1,1,1,-1,0,0,0,0,0,0,0}； Wherein, -128:127 represents a subcarrier index range of 20MHz.

8. A communication method characterized by comprising: The method comprises: The first station determines a long training field (LTF) sequence that satisfies: the LTF sequence value corresponding to the 52-tone DRU satisfies or or or wherein a i is an LTF sequence value corresponding to an i-th subcarrier with an index less than 0 in the odd-numbered subcarriers in the 52-tone DRU, b i is an LTF sequence value corresponding to an i-th subcarrier with an index greater than 0 in the odd-numbered subcarriers in the 52-tone DRU; or, a i is an LTF sequence value corresponding to an i-th subcarrier with an index less than 0 in the even-numbered subcarriers in the 52-tone DRU, b i is an LTF sequence value corresponding to an i-th subcarrier with an index greater than 0 in the even-numbered subcarriers in the 52-tone DRU. The first station sends a physical layer protocol data unit (PPDU), the PPDU comprising a long training field (LTF) determined according to a LTF sequence value corresponding to an allocated discrete resource unit (DRU).

9. The method of claim 8, wherein, The LTF is also determined according to a LTF sequence value corresponding to an unallocated DRU, the LTF sequence value corresponding to the unallocated DRU being 0.

10. The method according to claim 8 or 9, characterized in that, The discrete bandwidth of the DRU is 80MHz, and a difference between an index of an ith subcarrier with an index greater than 0 and an index of an ith subcarrier with an index less than 0 is 500.

11. A communication method, comprising: The method comprises: A second station receives a physical layer protocol data unit (PPDU), the PPDU comprising a long training field (LTF); The second station performs channel estimation according to the predefined LTF sequence and the LTF, the predefined LTF sequence satisfying: the LTF sequence value corresponding to the 52-tone DRU satisfies or or or wherein a i is an LTF sequence value corresponding to an i-th subcarrier with an index less than 0 in the odd-numbered subcarriers in the 52-tone DRU, b i is an LTF sequence value corresponding to an i-th subcarrier with an index greater than 0 in the odd-numbered subcarriers in the 52-tone DRU; or, a i is an LTF sequence value corresponding to an i-th subcarrier with an index less than 0 in the even-numbered subcarriers in the 52-tone DRU, b i is an LTF sequence value corresponding to an i-th subcarrier with an index greater than 0 in the even-numbered subcarriers in the 52-tone DRU.

12. The method of claim 11, wherein, The discrete bandwidth of an allocated discrete resource unit (DRU) is 80MHz, and a difference between an index of an ith subcarrier with an index greater than 0 and an index of an ith subcarrier with an index less than 0 is 500.

13. A communications device, characterized by The computer program product is executed to perform the method of any one of claims 1-12.

14. A computer-readable storage medium, characterized in that, The computer program product is executed to perform the method of any one of claims 1-12.

15. A computer program product, characterised in that, The computer program product is executed to perform the method of any one of claims 1-12.

16. A communication system, characterized by comprising a first station for performing the method according to any one of claims 1 to 4 and a second station for performing the method according to any one of claims 5 to 7; or, comprising a first station for performing the method according to any one of claims 8 to 10 and a second station for performing the method according to claim 11 or 12.

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