WO2022142577A1 - Ppdu的传输方法及相关装置 - Google Patents

Ppdu的传输方法及相关装置 Download PDF

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Publication number
WO2022142577A1
WO2022142577A1 PCT/CN2021/123193 CN2021123193W WO2022142577A1 WO 2022142577 A1 WO2022142577 A1 WO 2022142577A1 CN 2021123193 W CN2021123193 W CN 2021123193W WO 2022142577 A1 WO2022142577 A1 WO 2022142577A1
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Prior art keywords
subfield
preamble
ppdu
data field
sta
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PCT/CN2021/123193
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English (en)
French (fr)
Inventor
于健
狐梦实
西隆希米
潘金哲
淦明
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华为技术有限公司
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Publication of WO2022142577A1 publication Critical patent/WO2022142577A1/zh
Priority to US18/345,733 priority Critical patent/US20230344586A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053—Allocation of signaling, i.e. of overhead other than pilot signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/06—Notations for structuring of protocol data, e.g. abstract syntax notation one [ASN.1]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0091—Signaling for the administration of the divided path
    • H04L5/0094—Indication of how sub-channels of the path are allocated

Definitions

  • the present application relates to the technical field of wireless local area networks, and in particular, to a PPDU transmission method and related devices.
  • the physical layer protocol data unit (PPDU) proposed in the 802.11ax standard includes traditional preamble (legacy preamble, L-Preamble), high efficiency-signaling field-A (high efficient SIG A, HE-SIG-A ), high efficient-signaling field-B (high efficient SIG B, HE-SIG-B), high efficient short training field (HE-STF) and high efficient long training field (HE-STF) -LTF) and data.
  • HE-SIG-A and HE-SIG-B are used to indicate signaling information required for demodulating subsequent data fields.
  • HE-STF is used for automatic gain control (AGC) in the case of multiple input multiple output (multiple input multiple uutput, MIMO), and HE-LTF is used for channels on multiple space-time streams at the receiver of PPDU Take measurements.
  • AGC automatic gain control
  • MIMO multiple input multiple uutput
  • a WLAN (wireless local area network, wireless local area network) system usually considers a relatively static scene, that is, it is assumed that the channel will not change significantly within a certain period of time. Therefore, after the receiving end of the PPDU estimates the channel state information for the HE-LTF field, assuming that the channel state information of the subsequent data field is the same as that of the HE-LTF field, the channel state information estimated by the HE-LTF is used to decode the data field. Information.
  • the transmitting end can send such a PPDU structure, and it is not possible to realize mixed transmission to the device that does not support receiving the intermediate preamble and the device that supports receiving the intermediate preamble includes the intermediate preamble. code PPDU.
  • a PPDU needs to be transmitted to a device that does not support receiving an intermediate preamble and a device that supports receiving an intermediate preamble, it is necessary to transmit the PPDU twice before and after, which will cause a waste of resources.
  • the embodiments of the present application provide a PPDU transmission method and a related device, which can improve resource utilization efficiency.
  • an embodiment of the present application provides a method for transmitting a PPDU, including: generating a physical layer protocol data unit PPDU, where the PPDU includes a data field; and sending the PPDU to a first site and a second site.
  • the first station is a station that does not support receiving intermediate preambles
  • the second station is a station that supports receiving intermediate preambles.
  • the second data field transmitted by the second resource unit allocated by the second station includes an intermediate preamble subfield
  • the first data field transmitted by the first resource unit allocated by the first station includes a useful information subfield
  • the The useful information subfield includes useful data information
  • the useful information subfield is located before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field also includes a padding subfield, and the start position of the padding subfield is no later than the first OFDM symbol corresponding to the middle preamble subfield.
  • the first site may be a site of the first type or a site of the second type.
  • the first type of site is a site that does not support receiving the intermediate preamble and cannot read the signaling related to the intermediate preamble;
  • the second type of site is a site that does not support receiving the intermediate preamble, but can read the signaling related to the intermediate preamble. site.
  • the second station can read the intermediate preamble related signaling, and supports receiving the intermediate preamble.
  • the transmitting end simultaneously sends PPDUs to a first site that does not support receiving intermediate preambles and a second site that supports receiving intermediate preambles, and does not support receiving intermediate preambles.
  • the useful information subfield in the first data field received by the first station is located before the first OFDM symbol corresponding to the middle preamble subfield. This can improve the efficiency of resource utilization, and can avoid that in the Doppler scenario, the part carrying useful information in the first data field is too long, but the first station cannot estimate the channel in real time according to the intermediate preamble. There is an error in the reading of the data field, which helps to enable the first station that does not support receiving the intermediate preamble to accurately acquire useful data information in the data field.
  • the PPDU further includes a universal signaling field (universal SIG, U-SIG), the U-SIG includes an intermediate preamble indication subfield, and the intermediate preamble indication subfield indicates the
  • the data field includes an intermediate preamble subfield.
  • the mid-preamble indication subfield may also be referred to as the Doppler indication subfield. This application does not limit the name of the field.
  • At least one disregard bit in the U-SIG may be utilized to carry the mid-preamble indication subfield.
  • at least one disregard bit in the U-SIG may be used to indicate the subfield as an intermediate preamble. In this way, the first site of the first type will simply ignore it when reading the disregard bit. Using the disregard bit escape to indicate the intermediate preamble can ensure that the first type of station normally receives the data field.
  • At least one disregard bit in the U-SIG may be used to carry the intermediate preamble indication subfield
  • at least one validate bit in the U-SIG may be used to carry the intermediate preamble indication subfield.
  • at least one disregard bit or at least one validate bit in the U-SIG may be used to indicate the subfield as an intermediate preamble.
  • the PPDU further includes an extremely high throughput signaling field (extramely high throughput SIG, EHT-SIG), and the U-SIG or EHT-SIG includes an intermediate preamble period subfield, the intermediate preamble
  • the code period indication subfield indicates the period of the mid-preamble.
  • the intermediate preamble indication subfield When the value of the intermediate preamble indication subfield is the first value, indicating that the data field of the PPDU includes an intermediate preamble subfield, and the intermediate preamble period indication subfield indicates the period of the intermediate preamble;
  • the middle preamble indication subfield indicates that the data field of the PPDU does not include the middle preamble subfield, and the middle preamble period indication subfield indicates the space Number of streams, very high throughput - number of symbols for long training sequence EHT-LTF, ignore disregard or confirm validate.
  • At least one bit (for example, 1 bit) of the plurality of disregard bits may be used as the intermediate preamble indication subfield to indicate that the PPDU includes the intermediate preamble subfield, and the other at least one bit may be used as the intermediate preamble indication subfield.
  • a disregard bit of one bit (eg, 1 bit) as a mid-preamble period subfield indicates the mid-preamble period.
  • the number of space-time stream (number of space-time stream) in the user field can be used.
  • At least one bit in the time streams, NSS) subfield as the mid-preamble period subfield indicates the mid-preamble period.
  • the space-time stream subfield normally indicates the number of space-time streams.
  • the middle preamble indication subfield indicates that the PPDU includes a middle preamble subfield, or in other words, when the Doppler subfield indicates that the PPDU includes a middle preamble subfield, for example, when the middle preamble indication subfield indicates a first value (for example, 1) , the space-time stream subfield normally indicates the number of space-time streams.
  • At least one bit in the space-time stream subfield in the user field is used as an intermediate preamble period subfield to indicate the period of the intermediate preamble. For example, if the space-time stream subfield is 4 bits and the middle preamble indication subfield indicates that the PPDU includes the middle preamble subfield, 3 bits of the 4 bits are used to indicate the number of spatial streams, and the other 1 bit is used as the middle preamble period subfield Indicates the period of the mid-preamble.
  • the middle preamble subfield indicates the implementation manner of the period of the middle preamble, which can be any implementation manner when the first site is the first site of the first type.
  • At least one validate bit may be used to indicate the period of the intermediate preamble.
  • the U-SIG includes multiple disregard bits and multiple validate bits. At least one of the multiple disregard bits and multiple validate bits may be used as the intermediate preamble to indicate the subfield to indicate that the PPDU includes the intermediate preamble subfield, and at least one other bit of the validate bit may be used as the intermediate preamble period subfield to indicate the intermediate preamble. code period.
  • At least one of the multiple disregard bits and the multiple validate bits may be used as the intermediate preamble indication subfield to indicate that the PPDU includes the intermediate preamble subfield, and use The other at least one bit (eg, 1 bit) among the plurality of disregard bits and the plurality of validate bits as an intermediate preamble indication subfield indicates that the PPDU includes an intermediate preamble subfield.
  • U-SIG may be used. At least one bit (eg, 1 bit) in the number of EHT-LTF symbols subfield in the mid-preamble period subfield indicates the mid-preamble period.
  • the middle preamble indication subfield indicates that the PPDU does not include the middle preamble subfield, or in other words, when the Doppler subfield indicates that the PPDU does not include the middle preamble subfield, for example, the middle preamble indication subfield indicates the second value (eg 0), the number of EHT-LTF symbols subfield normally indicates the number of EHT-LTF symbols.
  • the middle preamble indication subfield indicates that the PPDU includes a middle preamble subfield, or in other words, when the Doppler subfield indicates that the PPDU includes a middle preamble subfield, for example, when the middle preamble indication subfield indicates a first value (for example, 1) , at least one bit in the EHT-LTF symbol number subfield is used as an intermediate preamble period subfield to indicate the period of the intermediate preamble.
  • the EHT-LTF symbol number subfield is 3 bits
  • the middle preamble indication subfield indicates that the PPDU includes the middle preamble subfield
  • 2 of the 3 bits are used to indicate the EHT-LTF symbol number
  • the other 1 bit is used as the middle
  • the preamble period subfield indicates the period of the mid-preamble.
  • the period of the middle preamble subfield may be specified by a standard, for example, the period of the middle preamble subfield may be specified to be 20 OFDM symbols.
  • the PPDU may not include the mid-preamble period indication subfield. In this way, the bits originally used to carry the mid-preamble period indication subfield can be used to carry other information, so that the PPDU can carry more information.
  • an embodiment of the present application provides a method for transmitting a PPDU, including:
  • the PPDU including a data field
  • the useful information subfield meets at least one of the following:
  • the useful information subfield is located before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is no later than the first OFDM symbol corresponding to the middle preamble subfield.
  • the first site may be a site of the first type or a site of the second type.
  • the first type of site is a site that does not support receiving the intermediate preamble and cannot read the signaling related to the intermediate preamble;
  • the second type of site is a site that does not support receiving the intermediate preamble, but can read the signaling related to the intermediate preamble. site.
  • the second station can read the intermediate preamble related signaling, and supports receiving the intermediate preamble.
  • the technical solutions of the embodiments of the present application can avoid that in a Doppler scenario, the part that carries useful information in the first data field is too long, but a site that does not support receiving the intermediate preamble cannot receive real-time information according to the intermediate preamble. Estimating the channel results in an error in reading the data field, which helps to enable a station that does not support receiving the intermediate preamble to accurately obtain useful data information in the data field.
  • the PPDU further includes a universal signaling field U-SIG, the U-SIG includes an intermediate preamble indication subfield, the intermediate preamble indication subfield indicates that the data field of the PPDU includes an intermediate preamble Code subfield.
  • the mid-preamble indication subfield may also be referred to as the Doppler indication subfield. This application does not limit the name of the field.
  • the intermediate preamble indication subfield reference may be made to the intermediate preamble indication subfield provided in the transmission method of the first aspect.
  • the PPDU further includes a very high throughput-signaling field EHT-SIG
  • the U-SIG or EHT-SIG includes an intermediate preamble period subfield
  • the intermediate preamble period indication subfield indicates The period of the mid-preamble.
  • the transmission method is used for a first type of station, and the parsing the PPDU to obtain the useful data information includes: identifying the intermediate preamble indication subfield in the U-SIG When the value of is the first value, the intermediate preamble indication subfield is ignored; the useful information subfield is acquired and parsed to obtain the useful data information.
  • the intermediate preamble indicator subfield indicates that the data field includes the intermediate preamble subfield, which is realized by the disregard bit escape instruction.
  • the first site is a site of the first type, it does not have the ability to read the disregard bit, then the first site This subfield will still be ignored according to the original meaning of the disregard bit, and then continue to receive the PPDU.
  • the first data field transmitted by the first resource unit is received, the first data field will be decoded to obtain the data in the first data field. Useful data information.
  • the transmission method is used for the second type of station, and the parsing the PPDU to obtain the useful data information includes: identifying the intermediate preamble indicator in the U-SIG When the value of the field is the first value, it is determined that the data field includes an intermediate preamble subfield; the period of the intermediate preamble is obtained according to the intermediate preamble period indication subfield; according to the period of the intermediate preamble, Obtain the useful information subfield located before the first OFDM symbol corresponding to the middle preamble subfield; obtain and parse the useful information subfield to obtain the useful data information.
  • the middle preamble indication subfield and the middle preamble period indication subfield are indicated by the escape indication of the disregard bit or the validate bit.
  • the first site When the first site is a site of the second type, the first site has the ability to read the disregard bit and the validate bit.
  • the first station can accurately read the meaning indicated by the intermediate preamble indication subfield and the intermediate preamble period indication subfield, and determine that the data field includes the intermediate preamble subfield and the period of the intermediate preamble subfield, so as to accurately obtain the intermediate preamble
  • the useful information subfield before the corresponding 1st OFDM symbol is a site of the second type.
  • the embodiments of the present application also provide a method for transmitting PPDU, including:
  • the PPDU includes a data field
  • the data field includes a data subfield and one or more intermediate preamble subfields set at intervals, the data subfield and the intermediate preamble subfield are at least two intervals; the The data subfield contains useful data information.
  • the PPDU is parsed to obtain the useful data information.
  • the intermediate preamble subfield is interspersed in the data field part, so that when the receiving end device receives the data field, it can estimate the channel according to the interspersed and set intermediate preamble, and obtain the latest channel information in time, so that the receiving end device can The device receives data fields better.
  • the present application provides a PPDU transmission apparatus, and the transmission apparatus can be used as a PPDU sending end device, or deployed in a PPDU sending end device.
  • the sending end device may be an access point or a station.
  • the transmission device includes:
  • a sending unit configured to send the PPDU to the first station and the second station.
  • the first station is a station that does not support receiving intermediate preambles
  • the second station is a station that supports receiving intermediate preambles.
  • the second data field transmitted by the second resource unit allocated by the second station includes an intermediate preamble subfield
  • the first data field transmitted by the first resource unit allocated by the first station includes a useful information subfield
  • the The useful information subfield includes useful data information
  • the useful information subfield is located before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is no later than the first OFDM symbol corresponding to the middle preamble subfield.
  • the first site may be a site of the first type or a site of the second type.
  • the first type of site is a site that does not support receiving the intermediate preamble and cannot read the signaling related to the intermediate preamble;
  • the second type of site is a site that does not support receiving the intermediate preamble, but can read the signaling related to the intermediate preamble. site.
  • the transmitting end simultaneously sends PPDUs to a first site that does not support receiving intermediate preambles and a second site that supports receiving intermediate preambles, and does not support receiving intermediate preambles.
  • the useful information subfield in the first data field received by the first station is located before the first OFDM symbol corresponding to the middle preamble subfield. This can improve the efficiency of resource utilization, and can avoid that in the Doppler scenario, the part carrying useful information in the first data field is too long, but the first station cannot estimate the channel in real time according to the intermediate preamble. There is an error in the reading of the data field, which helps to enable the first station that does not support receiving the intermediate preamble to accurately obtain useful data information in the data field.
  • the PPDU further includes a general signaling field U-SIG, the U-SIG includes an intermediate preamble indication subfield, the intermediate preamble indication subfield indicates that the data field of the PPDU includes an intermediate preamble Code subfield.
  • the mid-preamble indication subfield may also be referred to as the Doppler indication subfield. This application does not limit the name of the field.
  • the PPDU further includes a very high throughput-signaling field EHT-SIG
  • the U-SIG or EHT-SIG includes an intermediate preamble period subfield
  • the intermediate preamble period indication subfield indicates The period of the mid-preamble.
  • the intermediate preamble indication subfield When the value of the intermediate preamble indication subfield is the first value, indicating that the data field of the PPDU includes an intermediate preamble subfield, and the intermediate preamble period indication subfield indicates the period of the intermediate preamble;
  • the middle preamble indication subfield indicates that the data field of the PPDU does not include the middle preamble subfield, and the middle preamble period indication subfield indicates the space Number of streams, very high throughput - number of symbols for long training sequence EHT-LTF, ignore disregard or confirm validate.
  • the present application further provides a PPDU transmission device, and the transmission device can be used as a PPDU receiving end device, or deployed in a PPDU receiving end device.
  • the receiving end device may be a station or an access point.
  • the receiving end device may be, for example, the above-mentioned first site.
  • the transmission device includes:
  • a receiving unit configured to receive a PPDU, the PPDU includes a data field
  • a processing unit configured to parse the PPDU to obtain the useful data information
  • the useful information subfield meets at least one of the following:
  • the useful information subfield is located before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is no later than the first OFDM symbol corresponding to the middle preamble subfield.
  • the technical solutions of the embodiments of the present application can avoid that in a Doppler scenario, the part that carries useful information in the first data field is too long, but a site that does not support receiving the intermediate preamble cannot receive real-time information according to the intermediate preamble. Estimating the channel results in an error in reading the data field, which helps to enable a station that does not support receiving the intermediate preamble to accurately obtain useful data information in the data field.
  • the PPDU further includes a universal signaling field U-SIG, the U-SIG includes an intermediate preamble indication subfield, the intermediate preamble indication subfield indicates that the data field of the PPDU includes an intermediate preamble Code subfield.
  • the mid-preamble indication subfield may also be referred to as the Doppler indication subfield. This application does not limit the name of the field.
  • the intermediate preamble indication subfield reference may be made to the intermediate preamble indication subfield provided in the transmission method of the first aspect.
  • the PPDU further includes a very high throughput-signaling field EHT-SIG
  • the U-SIG or EHT-SIG includes an intermediate preamble period subfield
  • the intermediate preamble period indication subfield indicates The period of the mid-preamble.
  • the transmission device is a station of the first type, or is used for a station of the first type, and in terms of parsing the PPDU to obtain the useful data information, the processor is specifically configured to: identify the When the value of the middle preamble indication subfield in the U-SIG is the first value, ignore the middle preamble indication subfield; acquire and parse the useful information subfield to obtain the useful information subfield. Data information.
  • the intermediate preamble indicator subfield indicates that the data field includes the intermediate preamble subfield, which is realized by the disregard bit escape instruction.
  • the first site is a site of the first type, it does not have the ability to read the disregard bit, then the first site This subfield will still be ignored according to the original meaning of the disregard bit, and then continue to receive the PPDU.
  • the first data field transmitted by the first resource unit is received, the first data field will be decoded to obtain the data in the first data field. Useful data information.
  • the transmission device is a second type of station, or is used for a second type of station, and in terms of parsing the PPDU to obtain the useful data information, the processor is specifically configured to: identify When the value of the intermediate preamble indication subfield in the U-SIG is the first value, it is determined that the data field includes an intermediate preamble subfield; and the intermediate preamble period indication subfield is obtained according to the intermediate preamble period indication subfield.
  • the period of the preamble according to the period of the middle preamble, obtain the useful information subfield located before the first OFDM symbol corresponding to the middle preamble subfield; obtain and parse the useful information subfield to obtain the Useful data information.
  • the middle preamble indication subfield and the middle preamble period indication subfield are indicated by the escape indication of the disregard bit or the validate bit.
  • the first site When the first site is a site of the second type, the first site has the ability to read the disregard bit and the validate bit.
  • the first station can accurately read the meaning indicated by the intermediate preamble indication subfield and the intermediate preamble period indication subfield, and determine that the data field includes the intermediate preamble subfield and the period of the intermediate preamble subfield, so as to accurately obtain the intermediate preamble
  • the useful information subfield before the corresponding 1st OFDM symbol is a site of the second type.
  • the present application further provides a PPDU transmission apparatus, and the transmission apparatus can be used as a PPDU receiving end device, or deployed in a PPDU receiving end device.
  • the receiving end device may be a station or an access point.
  • the receiving end device may be, for example, the second site in the foregoing embodiment.
  • the transmission device includes:
  • a receiving unit configured to receive a PPDU, the PPDU includes a data field, the data field includes a data subfield and one or more intermediate preamble subfields set at intervals, and the interval between the data subfield and the intermediate preamble subfield is at least Two paragraphs; the data subfield contains useful data information.
  • a processing unit configured to parse the PPDU to obtain the useful data information.
  • the intermediate preamble subfield is interspersed in the data field part, so that when the receiving end device receives the data field, it can estimate the channel according to the interspersed and set intermediate preamble, and obtain the latest channel information in time, so that the receiving end device can The device receives data fields better.
  • the present application provides a PPDU transmission apparatus.
  • the transmission apparatus may be a communication device, or be deployed in a communication device.
  • the transmission device includes a processor coupled with the memory, and when the processor executes the computer program or instructions in the memory, the method of any one of the embodiments of the first aspect above is performed.
  • the apparatus further includes a memory.
  • the apparatus further includes a communication interface to which the processor is coupled.
  • processors there are one or more processors and one or more memories.
  • the memory may be integrated with the processor, or the memory may be provided separately from the processor.
  • the transceiver may include a transmitter (transmitter) and a receiver (receiver).
  • the transmission device is an access point or a station.
  • the communication interface may be a transceiver, or an input/output interface.
  • the transceiver may be a transceiver circuit.
  • the input/output interface may be an input/output circuit.
  • the transmission device is a chip or a system of chips.
  • the communication interface may be an input/output interface, an interface circuit, an output circuit, an input circuit, a pin or a related circuit, etc. on the chip or a chip system.
  • a processor may also be embodied as a processing circuit or a logic circuit.
  • the present application provides a communication system, which includes the transmission apparatuses of the fourth to sixth aspects.
  • the present application provides a computer program product, the computer program product comprising: a computer program (also referred to as code, or instruction), when the computer program is run, the computer executes the above-mentioned first to third aspects method in any of the possible implementations.
  • a computer program also referred to as code, or instruction
  • the present application provides a computer-readable storage medium, where the computer-readable medium stores a computer program (also referred to as code, or instruction), when it is run on a computer, to cause the computer to execute the above-mentioned first aspect to The method in any possible implementation manner of the third aspect.
  • a computer program also referred to as code, or instruction
  • the present application further provides a circuit, including: a processor and an interface, configured to execute a computer program or instruction stored in a memory, to execute any of the possible implementations of the first to third aspects above. method.
  • FIG. 1 is a schematic diagram of a network architecture of a communication system involved in an embodiment of the application
  • FIG. 2 is a schematic structural diagram of a transmission device according to an embodiment of the application.
  • FIG. 3 is a schematic structural diagram of a chip according to an embodiment of the present application.
  • 4A is a schematic structural diagram of a PPDU involved in the application.
  • 4B is another schematic structural diagram of the PPDU involved in the application.
  • 5 is another schematic structural diagram of the PPDU involved in the application.
  • 6A is a schematic flowchart of sending PPDU involved in the application
  • 6B is another schematic flowchart of sending PPDU involved in the application.
  • 6C is a schematic structural diagram of an A-MPDU involved in the application.
  • FIG. 7A is a schematic flowchart of a method for transmitting a PPDU according to an embodiment of the present application
  • FIG. 7B is another schematic flowchart of a method for transmitting a PPDU according to an embodiment of the present application.
  • FIG. 7C is another schematic flowchart of a method for transmitting a PPDU according to an embodiment of the present application.
  • 7D is another schematic flowchart of a method for transmitting a PPDU according to an embodiment of the present application.
  • 8A is a schematic diagram of a scenario of PPDU transmission according to an embodiment of the present application.
  • 8B is a schematic diagram of a scenario of PPDU transmission according to an embodiment of the present application.
  • 8C is a schematic diagram of a scenario of PPDU transmission according to an embodiment of the present application.
  • 9A is a schematic diagram of a scenario of PPDU transmission according to an embodiment of the present application.
  • FIG. 9B is a schematic diagram of a scenario of PPDU transmission according to an embodiment of the present application.
  • 9C is a schematic diagram of a scenario of PPDU transmission according to an embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of an apparatus for transmitting a PPDU according to an embodiment of the present application.
  • FIG. 11 is a schematic structural diagram of another PPDU transmission apparatus according to an embodiment of the present application.
  • FIG. 12 is a schematic structural diagram of another apparatus for transmitting a PPDU according to an embodiment of the present application.
  • FIG. 1 is a schematic diagram of a network structure provided by an embodiment of the present application, and the network structure may include one or more access point (access point, AP) type sites and one or more non-access point type sites (none access point station, non-AP STA).
  • access point access point
  • non-AP STA one access point station
  • the access point type station is referred to as an access point (AP) herein
  • the non-access point type station is referred to as a station (STA).
  • the APs are, for example, AP1 and AP2 in FIG. 1
  • the STAs are, for example, STA1 and STA2 in FIG. 1 .
  • the access point can be the access point for terminal devices (such as mobile phones) to enter the wired (or wireless) network. It is mainly deployed in homes, buildings and campuses, with a typical coverage radius ranging from tens of meters to hundreds of meters. Of course, also Can be deployed outdoors.
  • the access point is equivalent to a bridge connecting the wired network and the wireless network. Its main function is to connect the various wireless network clients together, and then connect the wireless network to the Ethernet.
  • the access point may be a terminal device (such as a mobile phone) or a network device (such as a router) with a wireless fidelity (wreless-fidelity, WiFi) chip.
  • the access point can be a device supporting the 802.11be standard.
  • the access point may also be a device that supports multiple wireless local area networks (WLAN) standards of the 802.11 family, such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.
  • WLAN wireless local area networks
  • the access point in this application may be an extremely high throughput (Extramely High Throughput, EHT) AP, or may be an access point applicable to a future generation of WiFi standards.
  • EHT extremely high throughput
  • the access point may include a processor and a transceiver, where the processor is used to control and manage actions of the access point, and the transceiver is used to receive or send information.
  • the station may be a wireless communication chip, a wireless sensor or a wireless communication terminal, etc., and may also be called a user.
  • a site can be a mobile phone that supports WiFi communication, a tablet that supports WiFi communication, a set-top box that supports WiFi communication, a smart TV that supports WiFi communication, a smart wearable device that supports WiFi communication, or a smart wearable that supports WiFi communication.
  • Vehicle communication equipment and computers that support WiFi communication functions, etc.
  • the site can support the 802.11be standard.
  • the station can also support multiple wireless local area networks (WLAN) systems of the 802.11 family, such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.
  • WLAN wireless local area networks
  • the station may include a processor and a transceiver, the processor is used to control and manage the actions of the access point, and the transceiver is used to receive or transmit information.
  • the station in this application may be a high efficient (HE) STA or an extremely high throughput (extramely high throughput, EHT) STA, and may also be a STA applicable to a future generation WiFi standard.
  • HE high efficient
  • EHT extremely high throughput
  • access points and sites can be devices used in the Internet of Vehicles, IoT nodes, sensors, etc. in the Internet of Things (IoT), smart cameras in smart homes, smart remote controls, smart water meters, and electricity meters. And sensors in smart cities, etc.
  • IoT Internet of Things
  • the access points and sites involved in the embodiments of the present application may also be collectively referred to as a PPDU transmission device, which may include a hardware structure and a software module, and implement the above in the form of a hardware structure, a software module, or a hardware structure plus a software module. each function.
  • a certain function of the above functions may be implemented in the form of a hardware structure, a software module, or a hardware structure plus a software module.
  • FIG. 2 is a schematic structural diagram of a device for transmitting a PPDU according to an embodiment of the present application.
  • the transmission apparatus 200 may include: a processor 201 , a transceiver 205 , and optionally a memory 202 .
  • the transceiver 205 may be referred to as a transceiver unit, a transceiver, or a transceiver circuit, etc., for implementing a transceiver function.
  • the transceiver 205 may include a receiver and a transmitter, the receiver may be called a receiver or a receiving circuit, etc., for implementing a receiving function; the transmitter may be called a transmitter or a transmitting circuit, etc., for implementing a transmitting function.
  • Memory 202 Stored in memory 202 may be a computer program or software code or instructions 204, which may also be referred to as firmware.
  • the processor 201 can control the MAC layer and the PHY layer by running the computer program or software code or instruction 203 therein, or by calling the computer program or software code or instruction 204 stored in the memory 202, so as to realize the following aspects of the present application.
  • the data transmission method provided by the embodiment.
  • the processor 201 can be a central processing unit (central processing unit, CPU), and the memory 202 can be, for example, a read-only memory (read-only memory, ROM), or a random access memory (random access memory, RAM).
  • CPU central processing unit
  • the memory 202 can be, for example, a read-only memory (read-only memory, ROM), or a random access memory (random access memory, RAM).
  • the processor 201 and transceiver 205 described in this application may be implemented in integrated circuits (ICs), analog ICs, radio frequency integrated circuits (RFICs), mixed-signal ICs, application specific integrated circuits (ASICs), printed circuits board (printed circuit board, PCB), electronic equipment, etc.
  • ICs integrated circuits
  • RFICs radio frequency integrated circuits
  • ASICs application specific integrated circuits
  • PCB printed circuits board
  • electronic equipment etc.
  • the above-mentioned transmission apparatus 200 may further include an antenna 206, and each module included in the transmission apparatus 200 is only for illustration, and is not limited in this application.
  • the transmission apparatus 200 described in the above embodiments may be an access point or a station, but the scope of the transmission apparatus described in this application is not limited thereto, and the structure of the transmission apparatus may not be limited by FIG. 2 .
  • the transmission device may be a stand-alone device or may be part of a larger device.
  • the implementation form of the transmission device may be:
  • Independent integrated circuit IC or chip, or, chip system or subsystem
  • a set of one or more ICs, optionally, the IC set may also include storage for storing data and instructions components; (3) modules that can be embedded in other devices; (4) receivers, smart terminals, wireless devices, handsets, mobile units, in-vehicle devices, cloud devices, artificial intelligence devices, etc.; (5) others, etc. .
  • the chip or chip system shown in FIG. 3 includes a processor 301 and an interface 302 .
  • the number of processors 301 may be one or more, and the number of interfaces 302 may be multiple.
  • the chip or chip system may include memory 303 .
  • 802.11ax provides a high-efficiency single-user physical layer protocol data unit (HESU PPDU) structure for single-user transmission and multi-user transmission respectively, and a high-efficiency multi-user physical layer protocol data unit ((high). efficient multiple user physical layer protocol data unit, HE MU PPDU)
  • HESU PPDU high-efficiency single-user physical layer protocol data unit
  • FIG. 4A is a schematic structural diagram of the HE SU PPDU of 802.11ax.
  • HESU PPDU includes legacy short training field (L-STF), legacy long training field (L-LTF), legacy signaling field (L-SIG), repeating legacy Signaling Field (RL-SIG), High Efficiency Signaling Field A (HE-SIG A), High Efficiency Segment Training Field (HE-STF), High Efficiency Long Training Field (HE-LTF), Data Field and Packet Extension (packet extension, PE).
  • the HE MU PPDU has an additional HE-SIG-B field for resource unit allocation.
  • the bandwidth includes multiple resource units and is allocated to different STAs.
  • the Doppler effect will cause channel changes. If the number of symbols in the data field is too large (too long), the channel change will affect the received data field.
  • the intermediate preamble can be interspersed in the data field of the PPDU, so that the receiving end device can estimate the channel according to the interspersed intermediate preamble when receiving the data field, and obtain the latest channel information in time. Therefore, the receiving end device can better receive the data field.
  • FIG. 4B a schematic structural diagram of a HE SU PPDU including an intermediate preamble provided by 802.11ax, the data field is interspersed with an intermediate preamble, and the station at the receiving end can estimate the channel according to the intermediate preamble.
  • the middle preamble consists of the HE-LTF field.
  • the station at the receiving end refreshes the channel according to the intermediate preamble, which helps to avoid channel changes caused by the Doppler effect in high-speed mobile scenarios, which may result in the inability to accurately read the data fields in the PPDU.
  • the structure of the PPDU including the intermediate preamble can be understood as a PPDU in Doppler mode.
  • the HEMU PPDU can also support the Doppler mode to avoid channel changes caused by the Doppler effect in high-speed mobile scenarios, resulting in the inability to accurately read the data fields in the PPDU.
  • the structure of the PPDU provided by the next-generation standard 802.11be Release 1 (R1) of 802.11ax is shown in Figure 5.
  • the PPDU provided by 802.11be R1 includes L-STF, L-LTF, L-SIG, RL-SIG, U- SIG, EHT-SIG, EHT-STF, EHT-LTF, Data Field and PE.
  • 802.11be R1 does not support Doppler mode, in other words, 802.11be R1 devices do not support receiving PPDUs containing intermediate preambles. However, some devices of 802.11be Release 2 (R2) may support receiving PPDUs containing intermediate preambles.
  • 802.11be R1 and 802.11be R2 are two versions of the 802.11be standard. 802.11be R2 may make further changes to the structure or signaling of the PPDU, but previous R1 devices will not understand 802.11be R2.
  • the receiving end device may be a device that supports receiving intermediate preambles, or may be a device that does not support receiving intermediate preambles.
  • the transmitting end device needs to send PPDUs to multiple receiving end devices, it is likely that multiple receiving end devices include both devices that support receiving intermediate preambles and devices that do not support receiving intermediate preambles.
  • the sending end device needs to send the PPDU twice in succession, which results in a great waste of resources.
  • the transmitting end can send multiple The receiving end device sends a PPDU that does not contain an intermediate preamble subfield. Due to the Doppler effect, the channel will change. If the number of symbols in the data field is too large (too long), the change of the channel will affect the received data field, which may lead to 802.11be that can better adapt to high-speed mobile scenarios. In high-speed mobile scenarios, R2 devices cannot accurately receive data fields and cannot fully utilize their performance. It will also cause 802.11be R1 devices to be unable to avoid the influence of the Doppler effect on the received data field, resulting in the inability to receive the data field accurately.
  • 802.11be R1 reserved bits are divided into two types: ignore disregard bits and validate bits.
  • the default value of both the disregard bit and the validate bit is 1.
  • the two reserved bits are non-default values (such as 0)
  • devices that support 802.11be R1 cannot understand the meaning of their indications. Specifically, if the disregard bit in the PPDU is a non-default value (eg, 0), the 802.11be R1 STA that receives the PPDU will choose to ignore it and continue to receive information.
  • the validate bit in the PPDU is a non-default value (for example, 0)
  • the 802.11be R1 station that receives the PPDU will directly stop receiving the information of the PPDU.
  • Devices that support 802.11be R2 can read the disregard bit and verify the meaning indicated by the validate bit.
  • the present application provides a solution capable of simultaneously transmitting PPDUs to a device that does not support receiving an intermediate preamble and a device that supports receiving an intermediate preamble.
  • the transmitting end device simultaneously transmits the PPDU to the first receiving end device that does not support receiving the intermediate preamble and the second receiving end device that supports receiving the intermediate preamble.
  • the second data field of the PPDU transmitted by the second resource unit allocated by the second receiving end device includes a data subfield and an intermediate preamble subfield; the first data field of the PPDU transmitted by the first resource unit allocated by the first receiving end device
  • the data field includes a useful information subfield, and the useful information subfield is located before the first OFDM symbol corresponding to the middle preamble subfield.
  • the useful information subfield includes useful data information.
  • the transmitting end device simultaneously transmits the PPDU to the device that does not support receiving the intermediate preamble and the device that supports receiving the intermediate preamble, thereby improving the resource utilization efficiency.
  • the length of the useful information subfield of the first receiving end device is smaller than the period of the intermediate preamble subfield, which can also reduce the Doppler effect caused by the accuracy of the data field received by the first receiving end device. Impact.
  • FIG. 6A and Figure 6B show the flow of the sending end device sending PPDU at the physical layer.
  • 6A is a schematic flowchart of sending PPDU corresponding to 802.11ax
  • FIG. 6B is a schematic flowchart of sending PPDU corresponding to 802.11be.
  • the data field includes a service (service) subfield and an aggregate medium access control protocol data unit (aggregate medium access control protocol data unit, A-MPDU) subfield.
  • the service subfield indicates the initial value of the scrambler.
  • the structure of the A-MPDU subfield is shown in Figure 6C, which includes the A-MPDU forward frame padding (pre end-of-frame padding, pre-EOF padding) part and the EOF delimiter.
  • the A-MPDU pre-EOF padding part carries useful data information, and the EOF delimiter is used to indicate the end of useful data information. That is to say, the A-MPDU pre-EOF padding part can be understood as a useful information subfield in this embodiment of the present application.
  • the A-MPDU pre-EOF padding part includes multiple A-MPDU subframes (A-MPDU subframe 1, A-MPDU subframe 2, ..., A-MPDU subframe n in Fig. 6C).
  • the technical solution of the present application will be described in detail below with reference to the PPDU transmission method of the embodiment of the present application.
  • the embodiments of this application are described with an embodiment in which an AP sends a PPDU to a STA.
  • the data transmission method of this application is also applicable to a scenario in which an AP sends a PPDU to an AP, and a scenario in which a STA sends a PPDU to a STA.
  • the transmitted PPDU and The names of the signaling fields are different, but their functions and functions are similar, and the embodiments of the present application will not describe them one by one.
  • the transmission method of PPDU may include the following steps:
  • the AP generates a PPDU
  • a PPDU includes a data field.
  • the PPDU may also include L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF, and PE.
  • L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF are parts of the physical layer header (or preamble) of the PPDU structure.
  • the AP sends a PPDU
  • the AP sends PPDUs to multiple STAs.
  • PPDUs can be transmitted using OFDMA.
  • the plurality of STAs include a first STA and a second STA.
  • the AP sends the PPDU to the first STA in the first resource element allocated to the first STA, and sends the PPDU to the second STA in the second resource element allocated to the second STA.
  • the data field in the PPDU transmitted by the first resource unit is different from the data field of the PPDU transmitted by the second resource unit.
  • the AP may send PPDUs to multiple STAs in a manner of aggregating PPDUs (aggregate PPDUs, A-PPDUs).
  • aggregate PPDUs aggregate PPDUs, A-PPDUs
  • the multiple PPDUs are combined into one A-PPDU.
  • the protocol versions supported by multiple PPDUs may be different.
  • the A-PPDU may be transmitted using OFDMA.
  • the first STA is a STA that does not support receiving an intermediate preamble
  • the second STA is a STA that supports receiving an intermediate preamble.
  • the second STA is a STA that supports receiving the middle preamble.
  • the second STA may be a STA that supports 802.11ax and supports reception of the mid-preamble.
  • the second STA may also be a STA that supports 802.11be R2 and supports receiving the middle preamble.
  • the second STA may also be a STA that supports WiFi standards after 802.11be R2 and supports receiving the middle preamble.
  • the first data field in the PPDU transmitted by the first resource unit includes a useful information subfield (for example, it may be called aggregate medium access control protocol data unit-frame padding (aggregate medium access control protocol data unit pre-end of frame padding, A-MPDU EOF padding)), the second data field of the PPDU transmitted by the second resource unit includes a data subfield and an intermediate preamble subfield.
  • the useful information subfield includes useful data information of the data field. In this embodiment of the present application, useful data information may also be referred to as useful information.
  • the useful information subfield includes a separator, and the separator includes a 1-bit EOF indication, which is used to indicate the end of the useful information subfield.
  • the useful information subfield is located before the first OFDM symbol corresponding to the middle preamble subfield. That is to say, the useful information subfield ends before the first OFDM symbol corresponding to the middle preamble subfield.
  • the first data field further includes a padding subfield, and the start position of the padding subfield is before the first OFDM symbol corresponding to the middle preamble subfield. It can also be said that the first data field further includes a padding subfield, and the start position of the padding subfield is no later than the first OFDM symbol corresponding to the middle preamble subfield.
  • the first STA may be a first type of STA or a second type of STA.
  • the first type of STA is a STA that does not support receiving intermediate preambles and cannot understand the signaling related to the intermediate preamble;
  • the second type of STA is a STA that does not support receiving intermediate preambles, but can read the intermediate preamble related signaling. STA.
  • the first type of STA can be a STA that supports 801.11be R1; the second type of STA can be a STA that supports 801.11be R2 and does not support receiving STA in the middle preamble.
  • the first STA acquires the useful information subfield in the PPDU to obtain useful data information contained in the first data field.
  • the first STA receives the PPDU from the first resource unit, and parses the PPDU to obtain the useful information subfield in the first data field.
  • the second STA acquires the data subfield in the second data field in the PPDU.
  • the second STA receives the PPDU from the second resource element, and parses the PPDU to obtain useful data information in the second data field.
  • the AP simultaneously sends a PPDU to the first STA that does not support receiving the middle preamble and the second STA that supports receiving the middle preamble, and the first STA that does not support receiving the middle preamble
  • the useful information subfield in the first data field received by a STA is located before the first OFDM symbol corresponding to the middle preamble subfield. This can improve the efficiency of resource utilization, and can also avoid that in the Doppler scenario, the part carrying useful information in the first data field is too long, but the first site cannot estimate the channel in real time according to the intermediate preamble. There is an error in the reading of the data field, which helps to enable the first STA that does not support receiving the intermediate preamble to accurately acquire useful data information in the data field.
  • the number of OFDM symbols of the preamble part of the PPDU transmitted by the first resource unit and the preamble part of the PPDU transmitted by the second resource unit are the same.
  • the number of OFDM symbols in the first data field transmitted by the first resource unit is the same as the number of OFDM symbols in the second data field transmitted by the second resource unit. In this way, the length of the PPDU transmitted by the first resource unit and the length of the PPDU transmitted by the second resource unit can be the same.
  • the second data field transmitted by the second resource unit includes n intermediate preamble subfields, where n ⁇ 1.
  • the n intermediate preamble subfields are spaced by M MA data symbols.
  • the data field transmitted by the first resource unit includes a padding subfield after the OFDM symbol corresponding to the first intermediate preamble subfield. In this way, the padding subfield can be set so that the number of OFDM symbols in the data field transmitted by the first resource unit is the same as the number of OFDM symbols in the data field transmitted by the second resource unit.
  • the first data field, in the position of the OFDM symbol corresponding to the middle preamble subfield in the second resource unit, may include a padding subfield or a middle preamble subfield.
  • PAPR peak-to-average power ratio
  • the following describes a solution in which the AP simultaneously transmits PPDUs to the first STA and the second STA when the first STA is a STA of the first type with reference to FIGS. 8A to 8C .
  • the first STA is a STA of the first type
  • the second STA is a STA that supports 802.11be R2 and supports receiving intermediate preambles.
  • the plurality of STAs may further include a third STA and a fourth STA, where the third STA is a STA that supports 802.11be R2 and supports receiving a middle preamble.
  • the fourth STA is an 802.11ax-enabled STA.
  • the first data field of the PPDU transmitted by the first resource unit to which the first STA is allocated includes a useful information subfield (data-R1) and a padding subfield (padding).
  • the second data field of the PPDU transmitted by the second resource unit allocated by the second STA includes a data subfield (data R2) and a plurality of middle preamble subfields (midamble). A plurality of intermediate preamble subfields are interspersed between the data subfields.
  • the third data field of the PPDU transmitted by the third resource unit allocated to the third STA includes a data subfield (data R2) and a plurality of middle preamble subfields (midamble). A plurality of intermediate preamble subfields are interspersed between the data subfields.
  • the fourth data field of the PPDU transmitted by the fourth resource unit to which the fourth STA is allocated includes a data subfield (data-HE) and a plurality of middle preamble subfields (midamble-HE). A plurality of intermediate preamble subfields are interspersed between the data subfields.
  • the data subfield (midamble-HE) is a useful information subfield of the STA sending 802.11ax.
  • the OFDM symbol corresponding to the middle preamble subfield transmitted by the second resource unit may also transmit the middle preamble subfield. That is to say, the first data field may also include an intermediate preamble subfield, and the time domain position of the intermediate preamble subfield is the same as the time domain position of the intermediate preamble subfield in the second data field.
  • the AP sends PPDUs to multiple STAs at the same time, a lower peak-to-average power ratio (PAPR) is guaranteed, and interference to other PPDUs can also be reduced.
  • PAPR peak-to-average power ratio
  • the data field transmitted by the first resource unit may only include the useful information subfield (data-R1), neither the padding subfield nor the intermediate preamble subfield. That is to say, the data field of the PPDU sent to the first STA may only carry useful information.
  • the following describes a solution for the AP to transmit PPDUs to the first STA and the second STA at the same time when the first STA is a second type of STA with reference to FIGS. 9A-9C .
  • the AP sends the PPDU to multiple STAs.
  • the plurality of STAs include a first STA, a second STA, a third STA, and a fourth STA.
  • the data field portions of the received PPDUs of the first STA, the second STA, the third STA and the fourth STA are different.
  • the first STA is a second type of STA (for example, an 802.11be R2 STA that does not support (without support, w/o support) receiving the intermediate preamble), the second STA and the third STA support 802.11be R2 and support (with support, w/support) STAs that receive the intermediate preamble and can read the relevant fields of the intermediate preamble.
  • the fourth STA is an 802.11ax STA.
  • the first data field of the PPDU transmitted by the first resource unit to which the first STA is allocated includes a useful information subfield (data-R2w/o support) and a padding subfield (padding).
  • the second data field of the PPDU transmitted by the second resource unit allocated by the second STA includes a data subfield (data-R2w/support) and a plurality of middle preamble subfields (midamble). A plurality of intermediate preamble subfields are interspersed between the data subfields.
  • the third data field of the PPDU transmitted by the third resource unit to which the third STA is allocated includes a data subfield (data R2w/support) and a plurality of middle preamble subfields (midamble). A plurality of intermediate preamble subfields are interspersed between the data subfields.
  • the fourth data field of the PPDU transmitted by the fourth resource unit to which the fourth STA is allocated includes a data subfield (data-HE) and a plurality of middle preamble subfields (midamble-HE). A plurality of intermediate preamble subfields are interspersed between the data subfields.
  • the AP can simultaneously transmit PPDUs to STAs that do not support receiving intermediate preambles and to multiple STAs that support receiving intermediate preambles, thereby effectively saving resources.
  • the symbol corresponding to the middle preamble subfield transmitted in the second resource unit may also be transmitted in the middle preamble subfield.
  • the first data field may also include an intermediate preamble subfield, and the time domain position of the intermediate preamble subfield is the same as the time domain position of the intermediate preamble subfield in the second data field.
  • PAPR peak-to-average power ratio
  • the first data field transmitted by the first resource unit may only include the useful information subfield, neither the padding subfield nor the middle preamble subfield. That is to say, the first data field of the PPDU sent to the first STA may only carry useful information. In this way, the first data field transmitted by the first resource unit can transmit more useful information.
  • the AP may only send the PPDU to the device that does not support the intermediate preamble and to a device that supports the intermediate preamble.
  • the AP may only send the PPDU to the first STA, the second STA and the third STA, and the AP may also send the PPDU only to the first STA and the fourth STA.
  • the PPDU further includes a U-SIG
  • the U-SIG includes an intermediate preamble indication subfield
  • a data field indicating the PPDU of the intermediate preamble indication subfield includes an intermediate preamble subfield.
  • the intermediate preamble indication subfield may also be referred to as a Doppler indication subfield. This application does not limit the name of the field.
  • At least one disregard bit in the U-SIG may be utilized to carry the mid-preamble indication subfield.
  • at least one disregard bit in the U-SIG may be used to indicate the subfield as an intermediate preamble. In this way, when the first STA of the first type reads the disregard bit, it will directly ignore it. Using the disregard bit escape to indicate the intermediate preamble can ensure that the STA of the first type normally receives the data field.
  • At least one disregard bit in the U-SIG may be used to carry the intermediate preamble indicator subfield
  • at least one validate bit in the U-SIG may be used to carry the intermediate preamble indicator subfield. field.
  • at least one disregard bit or at least one validate bit in the U-SIG may be used to indicate the subfield as an intermediate preamble.
  • the AP can transmit the PPDU to the first type of STA, the second type of STA and the second STA at the same time. This can better improve resource utilization efficiency.
  • the PPDU also includes the EHT-SIG.
  • the U-SIG or EHT-SIG includes an intermediate preamble period indication subfield for indicating the period of the intermediate preamble.
  • the intermediate preamble subfield indicates the period of the intermediate preamble.
  • At least one disregard bit may be used to indicate the period of the intermediate preamble. It should be understood that a number of disregard bits are included in the U-SIG. At least one bit (eg, 1 bit) of the plurality of disregard bits may be used as the intermediate preamble indication subfield to indicate that the PPDU includes the intermediate preamble subfield, and at least one other bit (eg, 1 bit) of the disregard bit may be used as the intermediate preamble period.
  • the subfield indicates the period of the mid-preamble.
  • the user field may be used.
  • SSS space-time streams
  • the space-time stream subfield normally indicates the number of space-time streams.
  • the middle preamble indication subfield indicates that the PPDU includes a middle preamble subfield, or in other words, when the Doppler subfield indicates that the PPDU includes a middle preamble subfield, for example, when the middle preamble indication subfield indicates a first value (for example, 1) , the space-time stream subfield normally indicates the number of space-time streams.
  • At least one bit in the space-time stream subfield in the user field is used as an intermediate preamble period subfield to indicate the period of the intermediate preamble. For example, if the space-time stream subfield is 4 bits and the middle preamble indication subfield indicates that the PPDU includes the middle preamble subfield, 3 bits of the 4 bits are used to indicate the number of spatial streams, and the other 1 bit is used as the middle preamble period subfield Indicates the period of the mid-preamble.
  • the middle preamble subfield indicates an implementation manner of the period of the middle preamble, which may be any of the foregoing implementation manners when the first STA is a STA of the first type.
  • At least one validate bit may be used to indicate the period of the intermediate preamble.
  • the U-SIG includes multiple disregard bits and multiple validate bits. At least one of the multiple disregard bits and multiple validate bits may be used as the intermediate preamble to indicate the subfield to indicate that the PPDU includes the intermediate preamble subfield, and at least one other bit of the validate bit may be used as the intermediate preamble period subfield to indicate the intermediate preamble. code period.
  • At least one of multiple disregard bits and multiple validate bits may be used as an intermediate preamble indication subfield to indicate that the PPDU includes an intermediate preamble subfield, and multiple The disregard bit and at least one other bit (eg, 1 bit) of the plurality of validate bits as an intermediate preamble indication subfield indicate that the PPDU includes an intermediate preamble subfield.
  • the number of EHT-LTF symbols in U-SIG can be used.
  • At least one bit (eg, 1 bit) in the symbols) subfield as an intermediate preamble period subfield indicates the period of the intermediate preamble.
  • the middle preamble indication subfield indicates that the PPDU does not include the middle preamble subfield, or in other words, when the Doppler subfield indicates that the PPDU does not include the middle preamble subfield, for example, the middle preamble indication subfield indicates the second value (eg 0), the number of EHT-LTF symbols subfield normally indicates the number of EHT-LTF symbols.
  • the middle preamble indication subfield indicates that the PPDU includes a middle preamble subfield, or in other words, when the Doppler subfield indicates that the PPDU includes a middle preamble subfield, for example, when the middle preamble indication subfield indicates a first value (for example, 1) , at least one bit in the EHT-LTF symbol number subfield is used as an intermediate preamble period subfield to indicate the period of the intermediate preamble.
  • the EHT-LTF symbol number subfield is 3 bits
  • the middle preamble indication subfield indicates that the PPDU includes the middle preamble subfield
  • 2 of the 3 bits are used to indicate the EHT-LTF symbol number
  • the other 1 bit is used as the middle
  • the preamble period subfield indicates the period of the mid-preamble.
  • the period of the middle preamble subfield may be specified by a standard, for example, the period of the middle preamble subfield may be specified to be 20 OFDM symbols.
  • the PPDU may not include the mid-preamble period indication subfield. In this way, the bits originally used to carry the mid-preamble period indication subfield can be used to carry other information, so that the PPDU can carry more information.
  • the following describes an implementation manner in which the first STA and the second STA receive the data field of the PPDU and obtain useful information in the data field.
  • the first STA is a first type of STA, as shown in the schematic flowchart in FIG. 7B , in step 703, the following steps 7031 and 7032 may be included, or the first STA obtains useful information in the data field
  • the specific process of the data information may include the following step 7031 or step 7032.
  • the first value may be the default value of 1, for example.
  • the intermediate preamble indication subfield indicates that the data field includes the intermediate preamble subfield, which is implemented by the disregard bit escape indication.
  • the first STA is the first type of STA, it does not have the ability to read the disregard bit. capability, then the first STA will still ignore this subfield according to the original meaning of the disregard bit, and then continue to receive the PPDU. Because the STA of the first type cannot truly read the meaning indicated by the intermediate preamble indication subfield, nor can it obtain information about whether the data field includes the intermediate preamble subfield, and will not obtain information about the period of the intermediate preamble. Information.
  • the first STA acquires and parses the useful information subfield to obtain useful data information.
  • the first STA After ignoring the intermediate preamble indication subfield, the first STA continues to receive the PPDU, and when receiving the first data field transmitted by the first resource unit, decodes the first data field to obtain useful data information in the first data field .
  • the first STA when the first STA receives the first data field, it obtains useful data information from the A-MPDU pre-EOF padding part (useful information subfield) of the A-MPDU subfield.
  • the EOF separator When the EOF separator is read, it is determined that the A-MPDU pre-EOF padding part ends, and the information read before the EOF separator and after the service subfield is useful data information.
  • the data field can also be normally received, and useful data information in the data field can be obtained.
  • the first STA is a second type of STA, as shown in the schematic flowchart in FIG. 7C , step 703 may include the following steps 7033 and 7034, or the first STA obtains the first data field in the
  • the specific process of the useful data information may include the following step 7031 or step 70032.
  • the first STA identifies that the value of the middle preamble indication subfield in the U-SIG is the first value, determine that the first data field includes the middle preamble subfield;
  • the first value may be the default value of 1, for example.
  • the intermediate preamble indication subfield indicates that the data field includes the intermediate preamble subfield, which is realized by escape indication of the disregard bit or the validate bit.
  • the first STA is a STA of the second type
  • the first STA has the ability to read the disregard bit and the validate bit.
  • the first STA can accurately read the meaning indicated by the middle preamble indication subfield, and determines that the data field includes the middle preamble subfield.
  • the first STA obtains the period of the intermediate preamble according to the intermediate preamble period indication subfield;
  • the first STA After the first STA determines that the first data field includes the intermediate preamble, it may continue to obtain the period of the intermediate preamble according to the intermediate preamble period indication subfield.
  • the intermediate preamble period indication subfield indicates the period of the intermediate preamble, which is realized by the escape indication of the disregard bit or the validate bit, or in other words, the period of the intermediate preamble is indicated by the disregard bit or the validate bit.
  • the first STA can accurately read the disregard bit and the validate bit, so that the first STA can accurately read the meaning indicated by the intermediate preamble indication subfield, and obtain the period of the intermediate preamble subfield.
  • the intermediate preamble period indication subfield indicates the period of the intermediate preamble, which is realized by at least one bit escape indication in the NSS subfield, or in other words, the period of the intermediate preamble is implemented through the NSS subfield. indicated by at least one bit.
  • the first STA determines that the data field includes the intermediate preamble subfield according to the intermediate preamble indication subfield, it can determine that at least one bit in the NSS subfield is used to indicate the period of the intermediate preamble, thereby The period of the middle preamble can be obtained according to at least one bit in the NSS subfield.
  • the intermediate preamble period indication subfield indicates the period of the intermediate preamble, which is realized by at least one bit escape indication in the EHT-LTF symbol number subfield, or in other words, the period of the intermediate preamble is realized through the EHT-LTF symbol number subfield. Indicated by at least one bit in the LTF Symbol Number subfield.
  • the first STA determines that the data field includes the middle preamble subfield according to the middle preamble indication subfield, it can determine that at least one bit in the EHT-LTF symbol number subfield is used to indicate the middle preamble. period, so that the period of the middle preamble can be obtained according to at least one bit in the EHT-LTF symbol number subfield.
  • the first STA acquires, according to the period of the intermediate preamble, a useful information subfield located before the first intermediate preamble subfield in one or more intermediate preamble subfields;
  • the first STA can determine the position where the intermediate preamble subfield appears according to the period of the intermediate preamble, so as to obtain the useful information field in the data field. In this way, the first STA can avoid mistaking the field after the first OFDM symbol corresponding to the middle preamble subfield as the useful information subfield, thereby ensuring the accuracy of the useful data information obtained by the first STA.
  • the first STA acquires and parses the useful information subfield to obtain useful data information.
  • step 7036 For the specific implementation of step 7036, reference may be made to the relevant description of step 7032 in the foregoing embodiment, which will not be described in detail here.
  • the first STA is a STA of the second type (for example, a STA that does not support receiving intermediate preambles and supports 802.11be R2)
  • the first STA cannot estimate the channel according to the intermediate preamble subfield
  • the first STA cannot Able to read the intermediate preamble indication subfield and correctly read the intermediate preamble period indication subfield, so that the period of the intermediate preamble can be obtained to accurately obtain the useful information before the first OFDM symbol corresponding to the intermediate preamble.
  • Information subfield for example, a STA that does not support receiving intermediate preambles and supports 802.11be R2
  • the second STA is a STA that supports receiving the middle preamble and can read the relevant fields of the middle preamble (eg, a STA that supports receiving the middle preamble and supports 802.11be R2).
  • the data field of the PPDU includes a data subfield and an intermediate preamble subfield.
  • the process of receiving the PPDU by the second STA may include the following steps 7041 to 7043 .
  • the second STA identifies that the value of the middle preamble indication subfield in the U-SIG is the first value, it is determined that the second data field includes the middle preamble subfield.
  • the first value may be the default value of 1, for example.
  • the middle preamble indication subfield indicates that the second data field includes the middle preamble subfield, which is realized by escape indication of the disregard bit or the validate bit.
  • the second STA has the ability to read the disregard bit and the validate bit. The second STA can accurately read the meaning indicated by the middle preamble indication subfield, and determines that the data field includes the middle preamble subfield.
  • the second STA acquires the period of the middle preamble according to the middle preamble period indication subfield.
  • the second STA After the second STA determines that the data field includes the intermediate preamble subfield, it may continue to obtain the period of the intermediate preamble according to the intermediate preamble period indication subfield.
  • the intermediate preamble period indication subfield indicates the period of the intermediate preamble, which is realized by the escape indication of the disregard bit or the validate bit, or in other words, the period of the intermediate preamble is indicated by the disregard bit or the validate bit.
  • the first STA can accurately read the disregard bit and the validate bit, so that the first STA can accurately read the meaning indicated by the intermediate preamble indication subfield, and obtain the period of the intermediate preamble subfield.
  • the intermediate preamble period indication subfield indicates the period of the intermediate preamble, which is realized by at least one bit escape indication in the NSS subfield, or in other words, the period of the intermediate preamble is implemented through the NSS subfield. indicated by at least one bit.
  • the first STA determines that the data field includes the middle preamble subfield according to the middle preamble indication subfield, it can determine that at least one bit in the NSS subfield is used to indicate the period of the middle preamble, so that The period of the middle preamble can be obtained according to at least one bit in the NSS subfield.
  • the intermediate preamble period indication subfield indicates the period of the intermediate preamble, which is realized by at least one bit escape indication in the EHT-LTF symbol number subfield, or in other words, the period of the intermediate preamble is realized through the EHT-LTF symbol number subfield. Indicated by at least one bit in the LTF Symbol Number subfield.
  • the first STA determines that the data field includes the middle preamble subfield according to the middle preamble indication subfield, it can determine that at least one bit in the EHT-LTF symbol number subfield is used to indicate the middle preamble. period, so that the period of the intermediate preamble can be obtained according to at least one bit in the EHT-LTF symbol number subfield.
  • the second STA acquires and parses the data subfield according to the period of the intermediate preamble.
  • the second STA can determine the position of the intermediate preamble subfield in the data field according to the period of the intermediate preamble, so as to determine the position of the data subfield to accurately receive and parse the data subfield.
  • the second data field may include one or more intermediate preamble subfields.
  • One or more intermediate subfields are interspersed between the data subfields.
  • the second STA When the second STA receives the second data field, it first receives the data subfield before the first intermediate preamble subfield, then receives the first intermediate preamble subfield, performs channel measurement according to the first intermediate preamble subfield, and performs channel measurement according to the first intermediate preamble subfield.
  • the data subfields after the 2nd intermediate preamble subfield, before the 3rd intermediate preamble subfield, . . . , and so on receive the remaining data subfields.
  • the second STA measures the channel according to the interspersed intermediate preamble subfields, and can obtain channel information more accurately, thereby being able to receive the data subfield more accurately.
  • FIG. 7D may be implemented independently, or may be implemented in combination with the embodiment corresponding to FIG. 7B or FIG. 7C .
  • the following describes a specific solution for realizing that the useful information subfield is located before the OFDM symbol corresponding to the middle preamble subfield when the AP encodes the data field for the data field sent to the first STA.
  • the AP When the AP sends the data field of the PPDU, it adds tail bits and pre-FEC padding to the field before encoding, then performs scrambling and encoding, and then inserts the intermediate preamble according to the period of the intermediate preamble. field, get the data field.
  • the device eg, STA
  • the device receiving the PPDU performs channel estimation according to the intermediate preamble subfield to update the channel information.
  • the device receiving the PPDU when decoding, decodes the part of the data field except the middle preamble subfield. That is to say, the device receiving the PPDU first removes the intermediate preamble subfield in the data field, and then decodes the remaining part of the data field.
  • the data field is usually encoded by low density parity check (low density parity check, LDPC) encoding or binary convolutional code (binary convolutional code, BCC) encoding. If the LDPC code is used for encoding, the code length and the number of codewords of the LDPC code need to be determined according to the number of available bits after encoding in the Data field.
  • low density parity check low density parity check
  • BCC binary convolutional code
  • the first STA is a STA of the first type
  • the first STA regards all the OFDM symbols after the EHT-LTF field and before the PE as a data field.
  • the AP generates the PPDU, in order to ensure that the length of the PPDU sent to each STA is the same, when adding pre-FEC padding to the data field, the length of the intermediate preamble needs to be taken into account.
  • LDPC encoding is used for the data field, and the codeword carrying the useful information ends before the 1st intermediate preamble subfield. In this way, it can be ensured that the first STA can correctly decode the data field to obtain useful information, and can avoid the Doppler effect from seriously affecting the receiving accuracy of the data field because the useful information subfield is too long.
  • BCC coding is used for the data field, and the number of symbols in the useful information subfield carrying useful information is less than the period of the middle preamble.
  • the AP sends PPDUs to multiple STAs.
  • the multiple STAs include a first STA and a second STA.
  • the data field of the PPDU sent by the AP to the first STA is:
  • the pre-FEC padding addition process includes the following steps:
  • N SYM,init,u encoded in the data field of the PPDU sent by the AP to each STA and the initial pre-FEC padding parameter a init.u .
  • the subscript u 0,1,...,N PPDU,total -1.
  • N PPDU,total represents the total number of PPDUs sent by the AP.
  • STBC space time block code
  • the receiving end device includes multiple STAs that support receiving intermediate preambles, determine that among one or more PPDUs containing intermediate preambles, the duration of the encoded data packet is the longest.
  • the index of the PPDU is obtained to obtain the initial symbol number N SYM,init of all PPDUs containing the intermediate preamble and the initial pre-FEC padding parameter a init .
  • N SYM,init N SYM,init,umax ;
  • N SYM, R1 N SYM +N MA ⁇ N EHT-LTF ;
  • N EHT-LTF represents the number of 4x symbols in the EHT-LTF field.
  • APEP_LENGTH is the parameter APEP_LENGTH in TXVECTOR, which indicates the number of bytes in the useful information subfield; M MA is the number of periodic symbols in the middle preamble subfield; N DBPS is the number of data bits contained in each symbol; N Service is the service in the PPDU. The number of bits in the subfield, the constant value is 16; N tail is the number of tail bits, which exists only in BCC.
  • N pla (N SYM,init +N MA ⁇ N EHT-LTF -1) ⁇ N DBPS +N DBPS,laSt ,
  • N avbits (N SYM, R1 -1) ⁇ N CBPS + N CBPS, last ;
  • N DBPS,last and N CBPS last represent the number of data bits and encoded bits in the last symbol.
  • the coding parameters of the PPDU are shown in Table 2.
  • the code length L LDPC, avbitS of all codewords finally obtained satisfies This ensures that the encoded code length cannot exceed the last symbol of the period, but can include useful information subfields.
  • the codes of all codewords take an upper limit And the number of data bits contained in each codeword L LDPC, pld satisfies Since the header codeword will be truncated by one more bit, it is assumed here that the code of all codewords takes the lower limit
  • the number of encoded bits N avbits,info contained in the codeword carrying useful information must satisfy: N avbits,info ⁇ N CW,info ⁇ L LDPC,avbits ⁇ M MA N CBPS .
  • N PAD,Pre-FEC (N SYM,R1 -1) ⁇ N DBPS +N DBPS,last -8 ⁇ APEP_LENGTH-N service -N tail ,
  • N DBPS,last represents the number of data bits in the last symbol, which is jointly determined by the pre-FEC padding factor a and N DBPS .
  • N PAD,Pre-FEC,PHY N PAD,Pre-FEC mod 8.
  • the first STA of the first type determines the length of the useful information subfield after reading the EOF delimiter in the A-MPDU of the Data field, and ignores the remaining padding subfields.
  • the intermediate preamble subfield in the data field of the PPDU sent to the second STA is 4 ⁇ EHT-LTF. This can prevent the first STA from continuing to demodulate the information in the data field after the start of the OFDM symbol corresponding to the intermediate preamble subfield when receiving the data field, resulting in misreading.
  • the first STA can read the intermediate preamble indication subfield, and can also obtain the period of the intermediate preamble. If the first STA does not have the ability to remove the intermediate preamble subfield from the data field and then decode it when receiving the data field, the AP sends the first STA to the PPDU data field in the pre-FEC padding adding process, and The process when the above-mentioned first STA is a first type of STA may be the same.
  • the structure of the data field of the PPDU sent by the AP to the first STA can be sent to the second STA together with the structure of the data field of the PPDU sent by the AP to the second STA.
  • the structure of the data field of the PPDU is the same.
  • an embodiment of the present application provides a device for transmitting a PPDU.
  • the transmission device may be used as a sending end device of the PPDU, or deployed on the sending end device of the PPDU.
  • the sending end device may be an access point or a station.
  • the transmission device 1000 includes:
  • a processing unit 1001 configured to generate a physical layer protocol data unit PPDU, where the PPDU includes a data field;
  • a sending unit 1002 configured to send the PPDU to a first site and a second site, where the first site is a site that does not support receiving intermediate preambles, and the second site is a site that supports receiving intermediate preambles;
  • the second data field transmitted by the second resource unit allocated by the second station includes an intermediate preamble subfield
  • the first data field transmitted by the first resource unit allocated by the first station includes a useful information subfield
  • the useful information subfield includes useful data information
  • the useful information subfield is located before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is no later than the first OFDM symbol corresponding to the middle preamble subfield.
  • the transmitting end simultaneously sends a PPDU to the first station that does not support receiving the middle preamble and the second station that supports receiving the middle preamble, and the first station that does not support receiving the middle preamble.
  • the useful information subfield in the first data field received by a station is located before the first OFDM symbol corresponding to the middle preamble subfield.
  • the part carrying useful information in the first data field is too long, but the first station cannot estimate the channel in real time according to the intermediate preamble. There is an error in the reading of the field, which helps to enable the first station that does not support receiving the intermediate preamble to accurately obtain useful data information in the data field.
  • the PPDU further includes a universal signaling field U-SIG, the U-SIG includes an intermediate preamble indication subfield, the intermediate preamble indication subfield indicates that the data field of the PPDU includes an intermediate preamble Code subfield.
  • the mid-preamble indication subfield may also be referred to as the Doppler indication subfield. This application does not limit the name of the field.
  • At least one disregard bit in the U-SIG may be utilized to carry the mid-preamble indication subfield.
  • at least one disregard bit in the U-SIG may be used to indicate the subfield as an intermediate preamble. In this way, the first site of the first type will simply ignore it when reading the disregard bit. Using the disregard bit escape to indicate the intermediate preamble can ensure that the first type of station normally receives the data field.
  • At least one disregard bit in the U-SIG may be used to carry the intermediate preamble indication subfield
  • at least one validate bit in the U-SIG may be used to carry the intermediate preamble indication subfield.
  • at least one disregard bit or at least one validate bit in the U-SIG may be used to indicate the subfield as an intermediate preamble.
  • the second station can determine whether there is an intermediate preamble subfield in the data field according to the intermediate preamble indication subfield, so that the data field can be read more accurately.
  • the PPDU further includes a very high throughput-signaling field EHT-SIG
  • the U-SIG or EHT-SIG includes an intermediate preamble period subfield
  • the intermediate preamble period indication subfield indicates The period of the mid-preamble.
  • the second station can obtain the period of the middle preamble subfield according to the middle preamble cycle indication subfield, and obtain the position of the middle preamble subfield in the data field, so that the data field can be accurately read except for the middle preamble. Parts other than fields to obtain useful data information.
  • the intermediate preamble indication subfield When the value of the intermediate preamble indication subfield is the first value, indicating that the data field of the PPDU includes an intermediate preamble subfield, and the intermediate preamble period indication subfield indicates the period of the intermediate preamble;
  • the middle preamble indication subfield indicates that the data field of the PPDU does not include the middle preamble subfield, and the middle preamble period indication subfield indicates the space Number of streams, very high throughput - number of symbols for long training sequence EHT-LTF, ignore disregard or confirm validate.
  • the fields carried by the same bit can be indicated with different meanings when the values of the intermediate preamble indication subfields are different, the transmission resources are fully utilized, and the utilization efficiency of the transmission resources is improved.
  • an embodiment of the present application provides an apparatus for transmitting a PPDU.
  • the transmission apparatus can be used as a receiving end device of the PPDU, or deployed at the receiving end device of the PPDU.
  • the receiving end device may be a station or an access point.
  • the receiving end device may be, for example, the first site in the foregoing embodiment.
  • the transmission device 1100 includes:
  • a receiving unit 1101 configured to receive a PPDU.
  • the PPDU includes a data field
  • a processing unit 1102 configured to parse the PPDU to obtain the useful data information
  • the useful information subfield meets at least one of the following:
  • the useful information subfield is located before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field also includes a padding subfield, and the start position of the padding subfield is before the first OFDM symbol corresponding to the middle preamble subfield;
  • the first data field further includes a padding subfield, and the start position of the padding subfield is no later than the first OFDM symbol corresponding to the middle preamble subfield.
  • the technical solutions of the embodiments of the present application can avoid that in a Doppler scenario, the part that carries useful information in the first data field is too long, but a site that does not support receiving the intermediate preamble cannot receive real-time information according to the intermediate preamble. Estimating the channel results in an error in reading the data field, which helps to enable a station that does not support receiving the intermediate preamble to accurately obtain useful data information in the data field.
  • the PPDU further includes a universal signaling field U-SIG, the U-SIG includes an intermediate preamble indication subfield, the intermediate preamble indication subfield indicates that the data field of the PPDU includes an intermediate preamble Code subfield.
  • the mid-preamble indication subfield may also be referred to as the Doppler indication subfield. This application does not limit the name of the field.
  • the intermediate preamble indication subfield reference may be made to the intermediate preamble indication subfield provided in the transmission method of the first aspect.
  • the PPDU further includes a very high throughput-signaling field EHT-SIG
  • the U-SIG or EHT-SIG includes an intermediate preamble period subfield
  • the intermediate preamble period indication subfield indicates The period of the mid-preamble.
  • the transmission device is a station of the first type, or is used for a station of the first type, and in terms of parsing the PPDU to obtain the useful data information, the processor is specifically configured to: identify the When the value of the middle preamble indication subfield in the U-SIG is the first value, ignore the middle preamble indication subfield; acquire and parse the useful information subfield to obtain the useful information subfield. Data information.
  • the intermediate preamble indicator subfield indicates that the data field includes the intermediate preamble subfield, which is realized by the disregard bit escape instruction.
  • the first site is a site of the first type, it does not have the ability to read the disregard bit, then the first site This subfield will still be ignored according to the original meaning of the disregard bit, and then continue to receive the PPDU.
  • the first data field transmitted by the first resource unit is received, the first data field will be decoded to obtain the data in the first data field. Useful data information.
  • the transmission device is a second type of station, or is used for a second type of station, and in terms of parsing the PPDU to obtain the useful data information, the processor is specifically configured to: identify When the value of the intermediate preamble indication subfield in the U-SIG is the first value, it is determined that the data field includes an intermediate preamble subfield; and the intermediate preamble period indication subfield is obtained according to the intermediate preamble period indication subfield.
  • the period of the preamble according to the period of the middle preamble, obtain the useful information subfield located before the first OFDM symbol corresponding to the middle preamble subfield; obtain and parse the useful information subfield to obtain the Useful data information.
  • the middle preamble indication subfield and the middle preamble period indication subfield are indicated by the escape indication of the disregard bit or the validate bit.
  • the first site When the first site is a site of the second type, the first site has the ability to read the disregard bit and the validate bit.
  • the first station can accurately read the meaning indicated by the intermediate preamble indication subfield and the intermediate preamble period indication subfield, and determine that the data field includes the intermediate preamble subfield and the period of the intermediate preamble subfield, so as to accurately obtain the intermediate preamble
  • the useful information subfield before the corresponding 1st OFDM symbol is a site of the second type.
  • an embodiment of the present application provides an apparatus for transmitting a PPDU.
  • the transmission apparatus can be used as a receiving end device of the PPDU, or deployed at the receiving end device of the PPDU.
  • the receiving end device may be a station or an access point.
  • the receiving end device may be, for example, the second site in the foregoing embodiment.
  • Transmission device 1200 includes:
  • a receiving unit 1201 is configured to receive a PPDU, where the PPDU includes a data field, the data field includes a data subfield and one or more intermediate preamble subfields set at intervals, and the interval between the data subfield and the intermediate preamble subfield is At least two paragraphs; the data subfield includes useful data information.
  • a processing unit 1202 configured to parse the PPDU to obtain the useful data information.
  • an intermediate preamble subfield is interspersed in the data field, so that when the receiving end device receives the data field, it can estimate the channel according to the interspersed and set intermediate preamble, and obtain the latest channel information in time, so that the receiving end can The device receives data fields better.
  • the receiving unit in the above-mentioned PPDU transmission apparatus may be implemented by the receiver of the above-mentioned PPDU transmission apparatus 200
  • the sending unit in the above-mentioned PPDU transmission apparatus may be implemented by the transmitter of the above-mentioned PPDU transmission apparatus 200
  • the processing unit in the above-mentioned PPDU transmission apparatus may be implemented by the processor 201 of the above-mentioned PPDU transmission apparatus 200 .
  • the size of the sequence numbers of the above-mentioned processes does not mean the sequence of execution, and the execution sequence of each process should be determined by its functions and internal logic, and should not be dealt with in the embodiments of the present application. implementation constitutes any limitation.
  • the disclosed system, apparatus and method may be implemented in other manners.
  • the apparatus embodiments described above are only illustrative.
  • the division of the units is only a logical function division. In actual implementation, there may be other division methods.
  • multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented.
  • the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit.
  • the functions, if implemented in the form of software functional units and sold or used as independent products, may be stored in a computer-readable storage medium.
  • the technical solution of the present application can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution.
  • the computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application.
  • the aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes .
  • the modules in the apparatus of the embodiment of the present application may be combined, divided and deleted according to actual needs.

Abstract

本申请提供了一种PPDU的传输方法及相关装置。方法包括：生成物理层协议数据单元PPDU，PPDU包括数据字段；向第一站点和第二站点发送PPDU，第一站点为不支持接收中间前导码的站点，第二站点为支持接收中间前导码的站点；其中，第二站点被分配的第二资源单元传输的第二数据字段包括中间前导码子字段，第一站点被分配的第一资源单元传输的第一数据字段包括有用信息子字段，有用信息子字段包括有用的数据信息，有用信息子字段位于中间前导码子字段对应的第1个OFDM符号之前。这样能够提升资源利用效率，而且能够避免在多普勒场景下，因第一数据字段中的承载有有用信息的部分过长，而导致对数据字段的读取有误差。

Description

PPDU的传输方法及相关装置
本申请要求于2021年01月04日提交中国国家知识产权局、申请号为202110005010.4、发明名称为“PPDU的传输方法及相关装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及无线局域网络技术领域，尤其涉及一种PPDU的传输方法及相关装置。
背景技术
802.11ax标准中提出的物理层协议数据单元(physicalp Protocol data unit，PPDU)包括传统前导码(legacy preamble,L-Preamble)、高效-信令字段-A(high efficient SIG A，HE-SIG-A)、高效-信令字段-B(high efficient SIG B，HE-SIG-B)、高效短训练序列(high efficient short training field，HE-STF)和高效长训练序列(high efficient long training field，HE-LTF)和数据。其中，HE-SIG-A和HE-SIG-B用于指示解调后续数据字段需要的信令信息。HE-STF用于进行多输入多输出(multiple input multiple uutput，MIMO)情况下的自动增益控制(automatic gain control，AGC)，HE-LTF用于PPDU的接收端对多个空时流上的信道进行测量。
WLAN(wireless local area network，无线局域网)系统通常考虑的场景为相对静止的场景，即假设信道在一定时间内不会有显著的变化。因此是在PPDU的接收端对HE-LTF字段估计完信道状态信息以后，假设后续的数据字段的信道状态信息与HE-LTF字段的相同，利用HE-LTF估计出的信道状态信息去解码数据字段的信息。
在802.11ax系统中考虑了一些中低速的多普勒场景，在这些场景中，信道会随着时间发生一定变化，因此提出了在数据字段中每隔M MA个数据符号插入中间前导码(Midamble)来实时刷新信道估计的方法。
然而，只有PPDU的接收端均支持包括中间前导码时，发送端才能发送这样的PPDU结构，并不能够实现向不支持接收中间前导码的设备以及支持接收中间前导码的设备混合传输包括中间前导码的PPDU。这样在需要向不支持接收中间前导码的设备以及支持接收中间前导码的设备传输PPDU时，需要前后分别传输两次PPDU，会造成资源浪费。
发明内容
本申请实施例提供了一种PPDU的传输方法及相关装置，能够提高资源利用效率。
第一方面，本申请实施方式提供一种PPDU的传输方法，包括：生成物理层协议数据单元PPDU，所述PPDU包括数据字段；和向第一站点和第二站点发送所述PPDU。
所述第一站点为不支持接收中间前导码的站点，所述第二站点为支持接收中间前导码的站点。
所述第二站点被分配的第二资源单元传输的第二数据字段包括中间前导码子字段，所述第一站点被分配的第一资源单元传输的第一数据字段包括有用信息子字段，所述有用信息子字段包括有用的数据信息。
有用信息子字段符合以下至少一项：
所述有用信息子字段位于所述中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置在中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置，不晚于中间前导码子字段对 应的第1个OFDM符号。
第一站点可以是第一类型的站点，也可以是第二类型的站点。第一类型的站点为不支持接收中间前导码，且无法读懂中间前导码相关信令的站点；第二类型的站点为不支持接收中间前导码，但是能够读懂中间前导码相关信令的站点。第二站点能够读懂中间前导码相关信令，且支持接收中间前导码。
本申请实施例的技术方案，在多普勒场景下，发送端同时向不支持接收中间前导码的第一站点和支持接收中间前导码的第二站点发送PPDU，而且不支持接收中间前导码的第一站点接收的第一数据字段中的有用信息子字段位于中间前导码子字段对应的第1个OFDM符号之前。这样能够提升资源利用效率，而且能够避免在多普勒场景下，因第一数据字段中的承载有有用信息的部分过长，但是第一站点却因为无法根据中间前导码实时估计信道而导致对数据字段的读取有误差，有助于使得不支持接收中间前导码的第一站点能够准确地获取数据字段中的有用的数据信息。
在一些实施方式中，所述PPDU还包括通用信令字段(universal SIG，U-SIG)，所述U-SIG包括中间前导码指示子字段，所述中间前导码指示子字段指示所述PPDU的数据字段包括中间前导码子字段。中间前导码指示子字段又可称作多普勒指示子字段。本申请对字段的名称不做限定。
例如，对于第一类型的站点，可利用U-SIG中的至少一个disregard比特来承载中间前导码指示子字段。或者说，U-SIG中的至少一个disregard比特可用于作为中间前导码指示子字段。这样，第一类型的第一站点在读取disregard比特时，会直接忽略。利用disregard比特转义指示中间前导码，能够保证第一类型的站点正常的接收数据字段。
又例如，对于第二类型的站点，可利用U-SIG中的至少一个disregard比特承载中间前导码指示子字段，也可以利用U-SIG中的至少一个validate比特来承载中间前导码指示子字段。换句话说，U-SIG中的至少一个disregard比特或至少一个validate比特可用于作为中间前导码指示子字段。可以理解，第二类型的站点能够读懂disregard比特和validate比特，那么利用disregard比特或validate比特承载中间前导码指示子字段，接收PPDU的第一站点是可以读懂中间前导码指示子字段所指示的含义的，从而能够实现准地接收数据字段中的有用信息子字段，已获得有用信息。
在一些实施方式中，所述PPDU还包括极高吞吐量信令字段(extramely high throughput SIG,EHT-SIG)，所述U-SIG或EHT-SIG包括中间前导码周期子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期。
在所述中间前导码指示子字段的值为第一数值时，指示所述PPDU的数据字段包括中间前导码子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期；
在所述中间前导码指示子字段的值为第二数值时，所述中间前导码指示子字段指示所述PPDU的数据字段不包括中间前导码子字段，所述中间前导码周期指示子字段指示空间流数、极高吞吐量-长训练序列EHT-LTF的符号数、不理会disregard或证实validate。
例如，第一站点为第一类型的第一站点时，可利用多个disregard比特中的至少一个比特(例如1比特)作为中间前导码指示子字段指示PPDU包括中间前导码子字段，利用另外的至少一个比特(例如1比特)的disregard比特作为中间前导码周期子字段指示中间前导码的周期。
第一站点为第一类型的第一站点时，在非多用户多输入多输出(multiple user multiple input  multiple output，MU-MIMO)场景下，可利用用户字段中的空时流(number of space-time streams，NSS)子字段中的至少一比特作为中间前导码周期子字段指示中间前导码的周期。
具体地，中间前导码指示子字段指示PPDU不包括中间前导码子字段时，或者说，当多普勒子字段指示PPDU不包括中间前导码子字段时，例如，中间前导码指示子字段指示第二数值(例如0)时，空时流子字段正常指示空时流数。中间前导码指示子字段指示PPDU包括中间前导码子字段时，或者说，当多普勒子字段指示PPDU包括中间前导码子字段时，例如，中间前导码指示子字段指示第一数值(例如1)时，空时流子字段正常指示空时流数用户字段中的空时流子字段中的至少一比特作为中间前导码周期子字段指示中间前导码的周期。例如，若空时流子字段为4比特，中间前导码指示子字段指示PPDU包括中间前导码子字段时，4比特中的3比特用于指示空间流数，另外1比特作为中间前导码周期子字段指示中间前导码的周期。
第一站点为第二类型的第一站点时，中间前导码子字段指示中间前导码的周期的实现方式，可采用上述第一站点为第一类型的第一站点时的任一种实现方式。
下面再提供几种第一站点为第二类型的第一站点时，中间前导码子字段指示中间前导码的周期的实现方式。
第一站点为第二类型的第一站点时，在一种可能的实现方式中，可利用至少一个validate比特指示中间前导码的周期。应理解，U-SIG中包括多个disregard比特和多个validate比特。可利用多个disregard比特和多个validate比特中的至少一个比特作为中间前导码指示子字段指示PPDU包括中间前导码子字段，利用另外的至少一个比特的validate比特作为中间前导码周期子字段指示中间前导码的周期。
具体地来说，第一站点为第二类型的第一站点时，可利用多个disregard比特和多个validate比特中的至少一个比特作为中间前导码指示子字段指示PPDU包括中间前导码子字段，利用多个disregard比特和多个validate比特中的另外的至少一个比特(例如1比特)作为中间前导码指示子字段指示PPDU包括中间前导码子字段。
第一站点为第二类型的第一站点时，在另一种可能的实现方式中，非多用户多输入多输出(multiple user multiple input multiple output，MU-MIMO)场景下，可利用U-SIG中的EHT-LTF符号数(number of EHT-LTF symbols)子字段中的至少一比(例如1比特)特作为中间前导码周期子字段指示中间前导码的周期。
具体地，中间前导码指示子字段指示PPDU不包括中间前导码子字段时，或者说，当多普勒子字段指示PPDU不包括中间前导码子字段时，例如，中间前导码指示子字段指示第二数值(例如0)时，EHT-LTF符号数子字段正常指示EHT-LTF符号数。中间前导码指示子字段指示PPDU包括中间前导码子字段时，或者说，当多普勒子字段指示PPDU包括中间前导码子字段时，例如，中间前导码指示子字段指示第一数值(例如1)时，EHT-LTF符号数子字段中的至少一比特作为中间前导码周期子字段指示中间前导码的周期。例如，若EHT-LTF符号数子字段为3比特，中间前导码指示子字段指示PPDU包括中间前导码子字段时，该3比特中的2比特用于指示EHT-LTF的符号数，另外1比特作为中间前导码周期子字段指示中间前导码的周期。
在一些实现方式中，中间前导码子字段的周期可以是标准规定的，例如，可以规定中间前导码子字段的周期为20个OFDM符号。这样PPDU可不包括中间前导码周期指示子字段。这样原用于承载中间前导码周期指示子字段的比特可用于承载其他信息，从而使得PPDU能 够承载更多的信息。
第二方面，本申请实施方式提供一种PPDU的传输方法，包括：
接收PPDU，所述PPDU包括数据字段，
解析所述PPDU以获得所述有用的数据信息；
其中，有用信息子字段符合以下至少一项：
所述有用信息子字段位于所述中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置在中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置，不晚于中间前导码子字段对应的第1个OFDM符号。
第一站点可以是第一类型的站点，也可以是第二类型的站点。第一类型的站点为不支持接收中间前导码，且无法读懂中间前导码相关信令的站点；第二类型的站点为不支持接收中间前导码，但是能够读懂中间前导码相关信令的站点。第二站点能够读懂中间前导码相关信令，且支持接收中间前导码。
本申请实施例的技术方案，能够避免在多普勒场景下，因第一数据字段中的承载有有用信息的部分过长，但是不支持接收中间前导码的站点却因为无法根据中间前导码实时估计信道而导致对数据字段的读取有误差，有助于使得不支持接收中间前导码的站点能够准确地获取数据字段中的有用的数据信息。
在一些实施方式中，所述PPDU还包括通用信令字段U-SIG，所述U-SIG包括中间前导码指示子字段，所述中间前导码指示子字段指示所述PPDU的数据字段包括中间前导码子字段。中间前导码指示子字段又可称作多普勒指示子字段。本申请对字段的名称不做限定。中间前导码指示子字段的相关描述可参考第一方面的传输方法中提供的中间前导码指示子字段。
在一些实施方式中，所述PPDU还包括极高吞吐量-信令字段EHT-SIG，所述U-SIG或EHT-SIG包括中间前导码周期子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期。中间前导码周期指示子字段的相关描述可参考第一方面的传输方法中提供的中间前导码周期指示子字段。
在一些实施方式中，该传输方法用于第一类型的站点，所述解析所述PPDU以获得所述有用的数据信息包括：识别出所述U-SIG中的所述中间前导码指示子字段的数值为所述第一数值时，忽略所述中间前导码指示子字段；获取并解析所述有用信息子字段，以获得所述有用的数据信息。
中间前导码指示子字段指示数据字段包括中间前导码子字段，是通过disregard比特转义指示实现的，第一站点为第一类型的站点时，并不具备读懂disregard比特的能力，那么第一站点仍然会按照原有的disregard比特的含义，忽略该子字段，然后继续接收PPDU接收到第一资源单元传输的第一数据字段时，对第一数据字段进行解码，得到该第一数据字段中的有用的数据信息。
在另一些实施方式中，该传输方法用于第二类型的站点，所述解析所述PPDU以获得所述有用的数据信息包括：识别出所述U-SIG中的所述中间前导码指示子字段的数值为所述第一数值时，确定所述数据字段包括中间前导码子字段；根据所述中间前导码周期指示子字段获取所述中间前导码的周期；根据所述中间前导码的周期，获取位于所述中间前导码子字段对应的第1个OFDM符号之前的有用信息子字段；获取并解析所述有用信息子字段，以获得 所述有用的数据信息。
中间前导码指示子字段和中间前导码周期指示子字段，是通过disregard比特或validate比特转义指示实现指示的。第一站点为第二类型的站点时，第一站点具备读懂disregard比特和validate比特的能力。第一站点能够准确读懂中间前导码指示子字段以及中间前导码周期指示子字段所指示的含义，确定数据字段包括中间前导码子字段，以及中间前导码子字段的周期，从而准确地获取中间前导码对应的第1个OFDM符号之前的有用信息子字段。
第三方面，本申请实施方式还提供一种PPDU的传输方法，包括：
接收PPDU，所述PPDU包括数据字段，所述数据字段包括数据子字段和一个或多个间隔设置的中间前导码子字段，所述数据子字段所述中间前导码子字段间隔为至少两段；所述数据子字段包括有用的数据信息。
解析所述PPDU以获得所述有用的数据信息。
这样的方案，在数据字段部分穿插设置中间前导码子字段，使得接收端设备在接收数据字段时，能够根据穿插设置的中间前导码对信道进行估计，及时获取最新的信道信息，从而能够使得接收端设备更好地接收数据字段。
第四方面，本申请提供一种PPDU的传输装置，该传输装置可作为PPDU的发送端设备，或者部署在PPDU的发送端设备。该发送端设备可以是接入点，也可以是站点。传输装置包括：
处理单元，用于生成PPDU；
发送单元，用于向第一站点和第二站点发送所述PPDU。
所述第一站点为不支持接收中间前导码的站点，所述第二站点为支持接收中间前导码的站点。
所述第二站点被分配的第二资源单元传输的第二数据字段包括中间前导码子字段，所述第一站点被分配的第一资源单元传输的第一数据字段包括有用信息子字段，所述有用信息子字段包括有用的数据信息。
有用信息子字段符合以下至少一项：
所述有用信息子字段位于所述中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置在中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置，不晚于中间前导码子字段对应的第1个OFDM符号。
第一站点可以是第一类型的站点，也可以是第二类型的站点。第一类型的站点为不支持接收中间前导码，且无法读懂中间前导码相关信令的站点；第二类型的站点为不支持接收中间前导码，但是能够读懂中间前导码相关信令的站点。
本申请实施例的技术方案，在多普勒场景下，发送端同时向不支持接收中间前导码的第一站点和支持接收中间前导码的第二站点发送PPDU，而且不支持接收中间前导码的第一站点接收的第一数据字段中的有用信息子字段位于中间前导码子字段对应的第1个OFDM符号之前。这样能够提升资源利用效率，而且能够避免在多普勒场景下，因第一数据字段中的承载有有用信息的部分过长，但是第一站点却因为无法根据中间前导码实时估计信道而导致对数据字段的读取有误差，有助于使得不支持接收中间前导码的第一站点能够准确地获取数据字段中的有用的数据信息。
在一些实施方式中，所述PPDU还包括通用信令字段U-SIG，所述U-SIG包括中间前导码指示子字段，所述中间前导码指示子字段指示所述PPDU的数据字段包括中间前导码子字段。中间前导码指示子字段又可称作多普勒指示子字段。本申请对字段的名称不做限定。
在一些实施方式中，所述PPDU还包括极高吞吐量-信令字段EHT-SIG，所述U-SIG或EHT-SIG包括中间前导码周期子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期。
在所述中间前导码指示子字段的值为第一数值时，指示所述PPDU的数据字段包括中间前导码子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期；
在所述中间前导码指示子字段的值为第二数值时，所述中间前导码指示子字段指示所述PPDU的数据字段不包括中间前导码子字段，所述中间前导码周期指示子字段指示空间流数、极高吞吐量-长训练序列EHT-LTF的符号数、不理会disregard或证实validate。
第五方面，本申请还提供一种PPDU的传输装置，该传输装置可作为PPDU的接收端设备，或者部署在PPDU的接收端设备。该接收端设备可以是站点，也可以是接入点。该接收端设备例如可以是上述的第一站点。传输装置包括：
接收单元，用于接收PPDU所述PPDU包括数据字段，
处理单元，用于解析所述PPDU以获得所述有用的数据信息；
其中，有用信息子字段符合以下至少一项：
所述有用信息子字段位于所述中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置在中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置，不晚于中间前导码子字段对应的第1个OFDM符号。
本申请实施例的技术方案，能够避免在多普勒场景下，因第一数据字段中的承载有有用信息的部分过长，但是不支持接收中间前导码的站点却因为无法根据中间前导码实时估计信道而导致对数据字段的读取有误差，有助于使得不支持接收中间前导码的站点能够准确地获取数据字段中的有用的数据信息。
在一些实施方式中，所述PPDU还包括通用信令字段U-SIG，所述U-SIG包括中间前导码指示子字段，所述中间前导码指示子字段指示所述PPDU的数据字段包括中间前导码子字段。中间前导码指示子字段又可称作多普勒指示子字段。本申请对字段的名称不做限定。中间前导码指示子字段的相关描述可参考第一方面的传输方法中提供的中间前导码指示子字段。
在一些实施方式中，所述PPDU还包括极高吞吐量-信令字段EHT-SIG，所述U-SIG或EHT-SIG包括中间前导码周期子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期。中间前导码周期指示子字段的相关描述可参考第一方面的传输方法中提供的中间前导码周期指示子字段。
在一些实施方式中，该传输装置为第一类型的站点，或者用于第一类型的站点，所述解析所述PPDU以获得所述有用的数据信息方面，处理器具体用于：识别出所述U-SIG中的所述中间前导码指示子字段的数值为所述第一数值时，忽略所述中间前导码指示子字段；获取并解析所述有用信息子字段，以获得所述有用的数据信息。
中间前导码指示子字段指示数据字段包括中间前导码子字段，是通过disregard比特转义指示实现的，第一站点为第一类型的站点时，并不具备读懂disregard比特的能力，那么第一 站点仍然会按照原有的disregard比特的含义，忽略该子字段，然后继续接收PPDU接收到第一资源单元传输的第一数据字段时，对第一数据字段进行解码，得到该第一数据字段中的有用的数据信息。
在另一些实施方式中，该传输装置为第二类型的站点，或者用于第二类型的站点，所述解析所述PPDU以获得所述有用的数据信息方面，处理器具体用于：识别出所述U-SIG中的所述中间前导码指示子字段的数值为所述第一数值时，确定所述数据字段包括中间前导码子字段；根据所述中间前导码周期指示子字段获取所述中间前导码的周期；根据所述中间前导码的周期，获取位于所述中间前导码子字段对应的第1个OFDM符号之前的有用信息子字段；获取并解析所述有用信息子字段，以获得所述有用的数据信息。
中间前导码指示子字段和中间前导码周期指示子字段，是通过disregard比特或validate比特转义指示实现指示的。第一站点为第二类型的站点时，第一站点具备读懂disregard比特和validate比特的能力。第一站点能够准确读懂中间前导码指示子字段以及中间前导码周期指示子字段所指示的含义，确定数据字段包括中间前导码子字段，以及中间前导码子字段的周期，从而准确地获取中间前导码对应的第1个OFDM符号之前的有用信息子字段。
第六方面，本申请还提供一种PPDU的传输装置，该传输装置可作为PPDU的接收端设备，或者部署在PPDU的接收端设备。该接收端设备可以是站点，也可以是接入点。该接收端设备例如可以是上述实施例中的第二站点。传输装置包括：
接收单元，用于接收PPDU，所述PPDU包括数据字段，所述数据字段包括数据子字段和一个或多个间隔设置的中间前导码子字段，所述数据子字段所述中间前导码子字段间隔为至少两段；所述数据子字段包括有用的数据信息。
处理单元，用于解析所述PPDU以获得所述有用的数据信息。
这样的方案，在数据字段部分穿插设置中间前导码子字段，使得接收端设备在接收数据字段时，能够根据穿插设置的中间前导码对信道进行估计，及时获取最新的信道信息，从而能够使得接收端设备更好地接收数据字段。
第七方面，本申请提供一种PPDU的传输装置。该传输装置可以为通信设备，或部署在通信设备。传输装置包括处理器，处理器与存储器耦合，当处理器执行存储器中的计算机程序或指令时，使得上述第一方面任一实施方式的方法被执行。
可选地，该装置还包括存储器。
可选地，该装置还包括通信接口，处理器与通信接口耦合。
可选的，处理器为一个或多个，存储器为一个或多个。
可选的，存储器可以与处理器集成在一起，或者存储器与处理器分离设置。
可选的，收发器中可以包括，发射机(发射器)和接收机(接收器)。
在一种实现方式中，该传输装置为接入点或站点。当该通信设备为接入点或站点时，通信接口可以是收发器，或，输入/输出接口。可选地，收发器可以为收发电路。可选地，输入/输出接口可以为输入/输出电路。
在另一种实现方式中，该传输装置为芯片或芯片系统。当该装置为芯片或芯片系统时，通信接口可以是该芯片或芯片系统上的输入/输出接口、接口电路、输出电路、输入电路、管脚或相关电路等。处理器也可以体现为处理电路或逻辑电路。
第八方面，本申请提供了一种通信系统，通信系统包括第四方面至第六方面的传输装置。
第九方面，本申请提供了一种计算机程序产品，计算机程序产品包括：计算机程序(也 可以称为代码，或指令)，当计算机程序被运行时，使得计算机执行上述第一方面至第三方面中任一种可能实现方式中的方法。
第十方面，本申请提供了一种计算机可读存储介质，计算机可读介质存储有计算机程序(也可以称为代码，或指令)当其在计算机上运行时，使得计算机执行上述第一方面至第三方面中任一种可能实现方式中的方法。
第十一方面，本申请还提供一种电路，包括：处理器和接口，用于执行存储器中存储的计算机程序或指令，执行上述第一方面至第三方面中任一种可能实现方式中的方法。
附图说明
图1为本申请实施例涉及的通信系统的网络架构示意图；
图2为本申请实施例的传输装置的结构示意图；
图3为本申请实施例的芯片的结构示意图；
图4A为本申请涉及的PPDU的结构示意图；
图4B为本申请涉及的PPDU的另一结构示意图；
图5为本申请涉及的PPDU的另一结构示意图；
图6A为申请涉及的发送PPDU的流程示意图；
图6B为申请涉及的发送PPDU的另一流程示意图；
图6C为申请涉及的A-MPDU的结构示意图；
图7A为本申请实施例的PPDU的传输方法的流程示意图；
图7B为本申请实施例的PPDU的传输方法的另一流程示意图；
图7C为本申请实施例的PPDU的传输方法的另一流程示意图；
图7D为本申请实施例的PPDU的传输方法的另一流程示意图；
图8A为本申请实施例的PPDU的传输的场景示意图；
图8B为本申请实施例的PPDU的传输的场景示意图；
图8C为本申请实施例的PPDU的传输的场景示意图；
图9A为本申请实施例的PPDU的传输的场景示意图；
图9B为本申请实施例的PPDU的传输的场景示意图；
图9C为本申请实施例的PPDU的传输的场景示意图；
图10为本申请实施例的PPDU的传输装置的结构示意图；
图11为本申请实施例的另一PPDU的传输装置的结构示意图；
图12为本申请实施例的又一PPDU的传输装置的结构示意图。
具体实施方式
下面将结合附图，对本申请中的技术方案进行描述。
以图1为例本申请所述的数据传输方法可适用的网络结构。图1是本申请实施例提供的网络结构的示意图，该网络结构可包括一个或多个接入点(access point，AP)类的站点和一个或多个非接入点类的站点(none access point station，non-AP STA)。为便于描述，本文将接入点类型的站点称为接入点(AP)，非接入点类的站点称为站点(STA)。AP例如为图1中的AP1和AP2，STA例如为图1中的STA1和STA2。
其中，接入点可以为终端设备(如手机)进入有线(或无线)网络的接入点，主要部署于家庭、大楼内部以及园区内部，典型覆盖半径为几十米至上百米，当然，也可以部署于户外。接入点相当于一个连接有线网和无线网的桥梁，主要作用是将各个无线网络客户端连接 到一起，然后将无线网络接入以太网。具体的，接入点可以是带有无线保真(wreless-fidelity，WiFi)芯片的终端设备(如手机)或者网络设备(如路由器)。
接入点可以为支持802.11be制式的设备。接入点也可以为支持802.11ax、802.11ac、802.11n、802.11g、802.11b及802.11a等802.11家族的多种无线局域网(wireless local area networks，WLAN)制式的设备。本申请中的接入点可以是极高吞吐量(extramely high throughput,EHT)AP，还可以是适用未来某代WiFi标准的接入点。
接入点可包括处理器和收发器，处理器用于对接入点的动作进行控制管理，收发器用于接收或发送信息。
站点可以为无线通讯芯片、无线传感器或无线通信终端等，也可称为用户。例如，站点可以为支持WiFi通讯功能的移动电话、支持WiFi通讯功能的平板电脑、支持WiFi通讯功能的机顶盒、支持WiFi通讯功能的智能电视、支持WiFi通讯功能的智能可穿戴设备、支持WiFi通讯功能的车载通信设备和支持WiFi通讯功能的计算机等等。
可选地，站点可以支持802.11be制式。站点也可以支持802.11ax、802.11ac、802.11n、802.11g、802.11b及802.11a等802.11家族的多种无线局域网(wireless local area networks，WLAN)制式。
站点可包括处理器和收发器，处理器用于对接入点的动作进行控制管理，收发器用于接收或发送信息。
本申请中的站点可以是高效(high efficient,HE)STA或极高吞吐量(extramely high throughput,EHT)STA，还可以是适用未来某代WiFi标准的STA。
例如，接入点和站点可以是应用于车联网中的设备，物联网(IoT，internet of things)中的物联网节点、传感器等，智慧家居中的智能摄像头，智能遥控器，智能水表电表，以及智慧城市中的传感器等。
本申请实施例中的所涉及的接入点和站点又可以统称为PPDU的传输装置，其可以包括硬件结构、软件模块，以硬件结构、软件模块、或硬件结构加软件模块的形式来实现上述各功能。上述各功能中的某个功能可以以硬件结构、软件模块、或者硬件结构加软件模块的方式来实现。
图2为本申请实施例提供的一种PPDU的传输装置的结构示意图。如图2所示，该传输装置200可包括：处理器201、收发器205，可选的还包括存储器202。
所述收发器205可以称为收发单元、收发机、或收发电路等，用于实现收发功能。收发器205可以包括接收器和发送器，接收器可以称为接收机或接收电路等，用于实现接收功能；发送器可以称为发送机或发送电路等，用于实现发送功能。
存储器202中可存储计算机程序或软件代码或指令204，该计算机程序或软件代码或指令204还可称为固件。处理器201可通过运行其中的计算机程序或软件代码或指令203，或通过调用存储器202中存储的计算机程序或软件代码或指令204，对MAC层和PHY层进行控制，以实现本申请下述各实施例提供的数据传输方法。
其中，处理器201可以为中央处理器(central processing unit，CPU)，存储器202例如可以为只读存储器(read-only memory，ROM)，或为随机存取存储器(random access memory，RAM)。
本申请中描述的处理器201和收发器205可实现在集成电路(integrated circuit，IC)、模拟IC、射频集成电路RFIC、混合信号IC、专用集成电路(application specific integrated circuit， ASIC)、印刷电路板(printed circuit board，PCB)、电子设备等上。
上述传输装置200还可以包括天线206，该传输装置200所包括的各模块仅为示例说明，本申请不对此进行限制。
如前所述，以上实施例描述中的传输装置200可以是接入点或者站点，但本申请中描述的传输装置的范围并不限于此，而且传输装置的结构可以不受图2的限制。传输装置可以是独立的设备或者可以是较大设备的一部分。例如所述传输装置的实现形式可以是：
(1)独立的集成电路IC，或芯片，或，芯片系统或子系统；(2)具有一个或多个IC的集合，可选的，该IC集合也可以包括用于存储数据，指令的存储部件；(3)可嵌入在其他设备内的模块；(4)接收机、智能终端、无线设备、手持机、移动单元、车载设备、云设备、人工智能设备等等；(5)其他等等。
对于传输装置的实现形式是芯片或芯片系统的情况，可参见图3所示的芯片或芯片系统的结构示意图。图3所示的芯片或芯片系统包括处理器301和接口302。其中，处理器301的数量可以是一个或多个，接口302的数量可以是多个。可选的，该芯片或芯片系统可以包括存储器303。
本申请实施例并且不限制权利要求书的保护范围和适用性。本领域技术人员可以在不脱离本申请实施例范围的情况下对本申请涉及的元件的功能和部署进行适应性更改，或酌情省略、替代或添加各种过程或组件。
802.11ax针对单用户传输和多用户传输分别提供了高效单用户物理层协议数据单元(high efficient single user physical layer protocol data unit，HE SU PPDU)结构，和高效多用户物理层协议数据单元((high efficient multiple user physical layer protocol data unit，HE MU PPDU)
如图4A所示的802.11ax的HE SU PPDU的结构示意图。HE SU PPDU包括传统短训练字段(legacy short training field,L-STF)、传统长训练字段(legacy long training field,L-LTF)、传统信令字段(legacy signal field,L-SIG)、重复传统信令字段(RL-SIG)、高效信令字段A(HE-SIG A)、高效段训练字段(HE-STF)、高效长训练字段(HE-LTF)、数据(data)字段和数据包扩展(packet extension，PE)。HE MU PPDU相比于HE SU PPDU，多了一个用于进行资源单元分配的HE-SIG-B字段。HE MU PPDU传输的场景下，带宽包含多个资源单元，分配给不同的STA。
在高速移动场景下，多普勒效应会造成信道变化，如果数据字段符号数过多(过长)，信道的变化会对接收数据字段造成的影响。在高速移动的场景下，可通过在PPDU的数据字段穿插设置中间前导码，使得接收端设备在接收数据字段时，能够根据穿插设置的中间前导码对信道进行估计，及时获取最新的信道信息，从而能够使得接收端设备更好地接收数据字段。
如图4B所示的802.11ax提供的包括中间前导码的HE SU PPDU的结构示意图，数据字段穿插有中间前导码，接收端的站点可根据中间前导码估计信道。其中，中间前导码由HE-LTF字段组成。接收端的站点根据中间前导码对信道进行刷新，在高速移动场景下，有助于避免因多普勒效应造成的信道变化，而造成不能准确地读取PPDU中的数据字段。这种包括中间前导码的PPDU的结构，可理解为多普勒模式的PPDU。类似的，HE MU PPDU也能够支持多普勒模式，以在高速移动场景下，避免因多普勒效应造成的信道变化，而造成不能准确地读取PPDU中的数据字段。
在802.11ax的下一代标准802.11be Release 1(R1)提供的PPDU的结构如图5所示，802.11be R1提供的PPDU包括L-STF、L-LTF、L-SIG、RL-SIG、U-SIG、EHT-SIG、EHT-STF、 EHT-LTF、数据字段和PE。802.11be R1并不支持多普勒模式，或者说，802.11be R1的设备，并不支持接收包含中间前导码的PPDU。而802.11be Release 2(R2)的一些设备，是有可能支持接收包含中间前导码的PPDU的。其中，802.11be R1和802.11be R2是802.11be标准的两个版本。802.11be R2可能会对PPDU的结构或者信令进行进一步更改，但是之前的R1设备是不会理解802.11be R2的。
这样接收端设备可能是支持接收中间前导码的设备，也可能是不支持接收中间前导码的设备。在发送端设备需要向多个接收端设备发送PPDU的场景下，很可能出现多个接收端设备既包括支持接收中间前导码的设备，也包括不支持接收中间前导码的设备。这种情况下，如果按照802.11ax提供的PPDU的发送方式发送PPDU，发送端设备需要先后发送两次PPDU，这样造成的资源浪费较大。
当需要向多个接收端设备发送包含中间前导码的PPDU时，若多个接收端设备既包括支持接收中间前导码的设备，也包括不支持接收中间前导码的设备，发送端可向多个接收端设备发送不包含中间前导码子字段的PPDU。由于多普勒效应会造成信道变化，如果数据字段符号数过多(过长)，信道的变化会对接收数据字段造成的影响，这样可能会导致本可以较好地适应高速移动场景的802.11be R2的设备在高速移动的场景下，无法准确地接收数据字段，不能充分发挥性能。也会导致802.11be R1的设备，无法避免多普勒效应对接收数据字段造成的影响，而导致无法准确地接收数据字段。
为便于描述本申请的技术方案，下面先介绍802.11be R1提供的EHT PPDU中的U-SIG的结构的一种示例，EHT PPDU中的U-SIG字段包含的子字段如表1所示。
表1
Figure PCTCN2021123193-appb-000001
Figure PCTCN2021123193-appb-000002
Figure PCTCN2021123193-appb-000003
802.11be R1中，保留比特(reserved bits)分为两种，分别为不理会disregard比特和证实validate比特。disregard比特和validate比特的默认值都为1。当两种保留比特为非默认值(例如0)时，支持802.11be R1的设备无法读懂其指示的含义。具体地，若PPDU中的disregard比特为非默认值(例如0)，接收该PPDU的802.11be R1的STA会选择忽略并继续接收信息。若PPDU中的validate比特为非默认值(例如0)，接收该PPDU的802.11be R1的站点会直接终止接收该PPDU的信息。支持802.11be R2的设备能够读懂disregard比特和证实validate比特所指示的含义。
本申请提供一种能够同时向不支持接收中间前导码的设备和支持接收中间前导码的设备传输PPDU的方案。具体地，发送端设备同时向不支持接收中间前导码的第一接收端设备和支持接收中间前导码的第二接收端设备传输PPDU。其中，第二接收端设备被分配的第二资源单元传输的PPDU的第二数据字段包括数据子字段和中间前导码子字段；第一接收端设备被分配的第一资源单元传输的PPDU的第一数据字段中，包括有用信息子字段，有用信息子字段位于中间前导码子字段对应的第1个OFDM符号之前。有用信息子字段包括有用的数据信息。这样，发送端设备同时向不支持接收中间前导码的设备和支持接收中间前导码的设备传输PPDU，提高资源利用效率。即使在高速移动的场景下，第一接收端设备的有用信息子字段的长度也小于中间前导码子字段的周期，这样也能够减轻多普勒效应对第一接收端设备接收数据字段的准确度造成的影响。
发送端设备在物理层发送PPDU的流程如图6A和图6B所示。其中图6A为802.11ax对应的发送PPDU的流程示意图，图6B为802.11be对应的发送PPDU的流程示意图。数据字段包括服务(service)子字段和聚合媒体访问控制协议数据单元(aggregate medium access  control protocol data unit，A-MPDU)子字段。服务子字段指示扰码器的初始值。A-MPDU子字段的结构如图6C所示，包含了A-MPDU前向帧结束填充(pre end-of-frame padding，pre-EOF padding)部分和EOF分隔符。
A-MPDU pre-EOF padding部分承载了有用的数据信息，EOF分隔符用于指示有用的数据信息的结束。也即是说，A-MPDU pre-EOF padding部分可理解为本申请实施例中的有用信息子字段。A-MPDU pre-EOF padding部分包括多个A-MPDU子帧(如图6C中的A-MPDU子帧1，A-MPDU子帧2，……，A-MPDU子帧n)。
下面结合本申请实施例的PPDU的传输方法详细阐述本申请的技术方案。本申请实施例以AP向STA发送PPDU的实施例进行说明，本申请的数据传输方法也适用于AP向AP发送PPDU的场景，STA向STA发送PPDU的场景，不同的场景中，传输的PPDU以及其中的信令字段的名称有所不同，但其功能和作用相类似，本申请实施例不一一赘述。
如图7A所示的流程示意图，本申请提供的PPDU的传输方法可包括以下步骤：
701、AP生成PPDU；
PPDU包括数据字段。可选的，该PPDU的结构可参考如图5所示的PPDU的结构示意图。PPDU可还包括L-STF、L-LTF、L-SIG、RL-SIG、U-SIG、EHT-SIG、EHT-STF、EHT-LTF和PE。
其中，L-STF、L-LTF、L-SIG、RL-SIG、U-SIG、EHT-SIG、EHT-STF、EHT-LTF为PPDU的物理层头部(或称前序部分)中的部分结构。
702、AP发送PPDU；
具体的，AP向多个STA发送PPDU。PPDU可以采用OFDMA传输。
多个STA包括第一STA和第二STA。AP在第一STA被分配的第一资源单元向第一STA发送PPDU，在第二STA被分配的第二资源单元向第二STA发送PPDU。第一资源单元传输的PPDU中的数据字段与第二资源单元传输的PPDU的数据字段是不同的。
AP可通过合并PPDU(aggregate PPDU，A-PPDU)的方式向多个STA发送PPDU。AP通过A-PPDU的方式向多个STA发送PPDU时，多个PPDU合并为一个A-PPDU。多个PPDU支持的协议版本可以是不同的。A-PPDU可以采用OFDMA传输。
本申请实施例中，第一STA为不支持接收中间前导码的STA，第二STA为支持接收中间前导码的STA。第二STA为支持接收中间前导码的STA。例如，第二STA可以是支持802.11ax，且支持接收中间前导码的STA。第二STA也可以是支持802.11be R2，且支持接收中间前导码的STA。第二STA也可以是支持802.11be R2之后的WiFi标准，且支持接收中间前导码的STA。
第一资源单元传输的PPDU中的第一数据字段包括有用信息子字段(例如，可称为聚合媒体访问控制协议数据单元-帧前填充(aggregate medium access control protocol data unit pre-end of frame padding，A-MPDU EOF padding))，第二资源单元传输的PPDU的第二数据字段包括数据子字段和中间前导码子字段。有用信息子字段包括数据字段的有用的数据信息。本申请实施例中，有用的数据信息又可称作有用信息。有用信息子字段中包含分隔符，分隔符中包括1比特的EOF指示，用于指示有用信息子字段的结束。
有用信息子字段位于中间前导码子字段对应的第1个OFDM符号之前。也即是说，有用信息子字段在中间前导码子字段对应的第1个OFDM符号之前结束。
或者说，第一数据字段还包括填充子字段，填充子字段的起始位置在中间前导码子字段对应的第1个OFDM符号之前。也可以说，第一数据字段还包括填充子字段，填充子字段的起始位置，不晚于中间前导码子字段对应的第1个OFDM符号。
本申请实施例中，第一STA可以是第一类型的STA，也可以是第二类型的STA。第一类型的STA为不支持接收中间前导码，且无法读懂中间前导码相关信令的STA；第二类型的STA为不支持接收中间前导码，但是能够读懂中间前导码相关信令的STA。
例如，若支持801.11be R2的设备能够读懂中间前导码相关的信令，第一类型的STA可为支持801.11be R1的STA；第二类型的STA可为支持801.11be R2，且不支持接收中间前导码的STA。
703、第一STA获取PPDU中的有用信息子字段，以得到第一数据字段中包含的有用的数据信息。
具体地，第一STA从第一资源单元接收PPDU，解析PPDU以获得第一数据字段中的有用信息子字段。
704、第二STA获取PPDU中的第二数据字段中的数据子字段。
第二STA从第二资源单元接收PPDU，解析PPDU以获得第二数据字段中的有用的数据信息。
本申请实施例的技术方案，在多普勒场景下，AP同时向不支持接收中间前导码的第一STA和支持接收中间前导码的第二STA发送PPDU，而且不支持接收中间前导码的第一STA接收的第一数据字段中的有用信息子字段位于中间前导码子字段对应的第1个OFDM符号之前。这样能够提升资源利用效率，也能够避免在多普勒场景下，因第一数据字段中的承载有有用信息的部分过长，但是第一站点却因为无法根据中间前导码实时估计信道而导致对数据字段的读取有误差，有助于使得不支持接收中间前导码的第一STA能够准确地获取数据字段中的有用的数据信息。
可选的，本申请实施例中，第一资源单元传输的PPDU的前序部分与第二资源单元传输的PPDU的前序部分的OFDM符号数是相同的。第一资源单元传输的第一数据字段的OFDM符号数与第二资源单元传输的第二数据字段的OFDM符号数是相同的。这样能够使得第一资源单元传输的PPDU的长度和第二资源单元传输的PPDU的长度是相同的。
第二资源单元传输的第二数据字段包括n个中间前导码子字段，n≥1。n个中间前导码子字段之间间隔M MA个数据符号。第一资源单元传输的数据字段，在第1个中间前导码子字段对应的OFDM符号之后，包括填充(padding)子字段。这样能够通过设置填充子字段，来使得第一资源单元传输的数据字段的OFDM符号数与第二资源单元传输的数据字段的OFDM符号数相同。
可选的，本申请实施例中，第一数据字段，在第二资源单元中的中间前导码子字段对应的OFDM符号的位置，可包括填充子字段或中间前导码子字段。这样在AP同时向多个STA发送PPDU时，保证较低的峰值平均功率比(peak to average power ratio，PAPR)，也能降低对其他PPDU的干扰。
下面结合图8A-图8C阐述第一STA是第一类型的STA时，AP同时向第一STA和第二STA传输PPDU的方案。
如图8A的PPDU的结构示意图，第一STA是第一类型的STA，第二STA是支持802.11be R2，且支持接收中间前导码的STA。多个STA还可以包括第三STA和第四STA，第三STA 是支持802.11be R2，且支持接收中间前导码的STA。第四STA是支持802.11ax的STA。
第一STA被分配的第一资源单元传输的PPDU的第一数据字段包括有用信息子字段(data-R1)和填充子字段(padding)。
第二STA被分配的第二资源单元传输的PPDU的第二数据字段包括数据子字段(data R2)和多个中间前导码子字段(midamble)。多个中间前导码子字段穿插设置在数据子字段之间。
第三STA被分配的第三资源单元传输的PPDU的第三数据字段包括数据子字段(data R2)和多个中间前导码子字段(midamble)。多个中间前导码子字段穿插设置在数据子字段之间。
第四STA被分配的第四资源单元传输的PPDU的第四数据字段包括数据子字段(data-HE)和多个中间前导码子字段(midamble-HE)。多个中间前导码子字段穿插设置在数据子字段之间。该数据子字段(midamble-HE)是发802.11ax的STA的有用信息子字段。
如图8B所示的PPDU的结构示意图，第一资源单元中，与第二资源单元传输中间前导码子字段对应的OFDM符号，也可以传输中间前导码子字段。也即是说，第一数据字段中，也可以包括中间前导码子字段，该中间前导码子字段的时域位置，与第二数据字段中的中间前导码子字段的时域位置是相同的。这样在AP同时向多个STA发送PPDU时，保证较低的峰值平均功率比(peak to average power ratio，PAPR)，也能降低对其他PPDU的干扰。
如图8C所示的PPDU的结构示意图，第一资源单元传输的数据字段可仅包括有用信息子字段(data-R1)，不包括填充子字段也不包括中间前导码子字段。也即是说，发送给第一STA的PPDU的数据字段，可仅承载有用信息。
下面结合图9A-图9C阐述第一STA是第二类型的STA时，AP同时向第一STA和第二STA传输PPDU的方案。
如图9A的PPDU的结构示意图，AP向多个STA发送PPDU。多个STA包括第一STA、第二STA、第三STA和第四STA。第一STA、第二STA、第三STA和第四STA的接收的PPDU的数据字段部分是不同的。第一STA是第二类型的STA(例如是不支持(without support，w/o support)接收中间前导码的802.11be R2的STA)，第二STA和第三STA是支持802.11be R2，且支持(with support，w/support)接收中间前导码，且能够读懂中间前导码相关字段的STA。第四STA是802.11ax的STA。
第一STA被分配的第一资源单元传输的PPDU的第一数据字段包括有用信息子字段(data-R2w/o support)和填充子字段(padding)。
第二STA被分配的第二资源单元传输的PPDU的第二数据字段包括数据子字段(data-R2w/support)和多个中间前导码子字段(midamble)。多个中间前导码子字段穿插设置在数据子字段之间。
第三STA被分配的第三资源单元传输的PPDU的第三数据字段包括数据子字段(data R2w/support)和多个中间前导码子字段(midamble)。多个中间前导码子字段穿插设置在数据子字段之间。
第四STA被分配的第四资源单元传输的PPDU的第四数据字段包括数据子字段(data-HE)和多个中间前导码子字段(midamble-HE)。多个中间前导码子字段穿插设置在数据子字段之间。
这样，AP可以同时向不支持接收中间前导码的STA，以及多种支持接收中间前导码的STA传输PPDU，有效地节省资源。
如图9B所示的PPDU的结构示意图，第一资源单元中，与第二资源单元传输中间前导码子字段对应的符号，也可以传输中间前导码子字段。也即是说，第一数据字段中，也可以包括中间前导码子字段，该中间前导码子字段的时域位置，与第二数据字段中的中间前导码子字段的时域位置是相同的。这样在AP同时向多个STA发送PPDU时，保证较低的峰值平均功率比(peak to average power ratio，PAPR)，也能降低对其他PPDU的干扰。
如图9C所示的PPDU的结构示意图，第一资源单元传输的第一数据字段可仅包括有用信息子字段，不包括填充子字段也不包括中间前导码子字段。也即是说，发送给第一STA的PPDU的第一数据字段，可仅承载有用信息。这样第一资源单元传输的第一数据字段可以传输更多的有用信息。
应理解，图8A-图9C对应的任一实施例中，AP可仅向不支持中间前导码的设备以及一种支持中间前导码的设备发送PPDU。例如，AP可仅向第一STA、第二STA和第三STA发送PPDU，AP也可以仅向第一STA和第四STA发送PPDU。
在一些可选的实施例中，PPDU还包括U-SIG，该U-SIG包括中间前导码指示子字段，中间前导码指示子字段的指示PPDU的数据字段包括中间前导码子字段。可选的，中间前导码指示子字段又可称作多普勒指示子字段。本申请对字段的名称不做限定。
例如，对于第一类型的第一STA，可利用U-SIG中的至少一个disregard比特来承载中间前导码指示子字段。或者说，U-SIG中的至少一个disregard比特可用于作为中间前导码指示子字段。这样，第一类型的第一STA在读取disregard比特时，会直接忽略。利用disregard比特转义指示中间前导码，能够保证第一类型的STA正常的接收数据字段。
又例如，对于第二类型的第一STA，可利用U-SIG中的至少一个disregard比特承载中间前导码指示子字段，也可以利用U-SIG中的至少一个validate比特来承载中间前导码指示子字段。换句话说，U-SIG中的至少一个disregard比特或至少一个validate比特可用于作为中间前导码指示子字段。可以理解，第二类型的第一STA能够读懂disregard比特和validate比特，那么利用disregard比特或validate比特承载中间前导码指示子字段，接收PPDU的第一STA是可以读懂中间前导码指示子字段所指示的含义的，从而能够实现准地接收数据字段中的有用信息子字段，以获得有用信息。
可选的，若采用disregard比特来承载中间前导码指示子字段，AP可同时向第一类型的STA、第二类型的STA以及第二STA传输PPDU。这样可以更好地提升资源利用效率。
进一步地，PPDU还包括EHT-SIG。U-SIG或EHT-SIG包括中间前导码周期指示子字段，用于指示中间前导码的周期。
本申请实施例中，针对第一STA为第一类型的STA和第二类型的STA，分别提供了几种中间前导码子字段指示中间前导码的周期的实现方式。
第一STA为第一类型的第一STA时，在一种可能的实现方式中，可利用至少一个disregard比特指示中间前导码的周期。应理解，U-SIG中包括多个disregard比特。可利用多个disregard比特中的至少一个比特(例如1比特)作为中间前导码指示子字段指示PPDU包括中间前导码子字段，利用另外的至少一个比特(例如1比特)的disregard比特作为中间前导码周期子字段指示中间前导码的周期。
第一STA为第一类型的第一STA时，在一种可能的实现方式中，在非多用户多输入多输 出(multiple user multiple input multiple output，MU-MIMO)场景下，可利用用户字段中的空时流(number of space-time streams，NSS)子字段中的至少一比特作为中间前导码周期子字段指示中间前导码的周期。
具体地，中间前导码指示子字段指示PPDU不包括中间前导码子字段时，或者说，当多普勒子字段指示PPDU不包括中间前导码子字段时，例如，中间前导码指示子字段指示第二数值(例如0)时，空时流子字段正常指示空时流数。中间前导码指示子字段指示PPDU包括中间前导码子字段时，或者说，当多普勒子字段指示PPDU包括中间前导码子字段时，例如，中间前导码指示子字段指示第一数值(例如1)时，空时流子字段正常指示空时流数用户字段中的空时流子字段中的至少一比特作为中间前导码周期子字段指示中间前导码的周期。例如，若空时流子字段为4比特，中间前导码指示子字段指示PPDU包括中间前导码子字段时，4比特中的3比特用于指示空间流数，另外1比特作为中间前导码周期子字段指示中间前导码的周期。
第一STA为第二类型的STA时，中间前导码子字段指示中间前导码的周期的实现方式，可采用上述第一STA为第一类型的STA时的任一种实现方式。
下面再提供几种第一STA为第二类型的STA时，中间前导码子字段指示中间前导码的周期的实现方式。
在一种可能的实现方式中，可利用至少一个validate比特指示中间前导码的周期。应理解，U-SIG中包括多个disregard比特和多个validate比特。可利用多个disregard比特和多个validate比特中的至少一个比特作为中间前导码指示子字段指示PPDU包括中间前导码子字段，利用另外的至少一个比特的validate比特作为中间前导码周期子字段指示中间前导码的周期。
具体地来说，第一STA为第二类型的STA时，可利用多个disregard比特和多个validate比特中的至少一个比特作为中间前导码指示子字段指示PPDU包括中间前导码子字段，利用多个disregard比特和多个validate比特中的另外的至少一个比特(例如1比特)作为中间前导码指示子字段指示PPDU包括中间前导码子字段。
在另一种可能的实现方式中，非多用户多输入多输出(multiple user multiple input multiple output，MU-MIMO)场景下，可利用U-SIG中的EHT-LTF符号数(number of EHT-LTF symbols)子字段中的至少一比(例如1比特)特作为中间前导码周期子字段指示中间前导码的周期。
具体地，中间前导码指示子字段指示PPDU不包括中间前导码子字段时，或者说，当多普勒子字段指示PPDU不包括中间前导码子字段时，例如，中间前导码指示子字段指示第二数值(例如0)时，EHT-LTF符号数子字段正常指示EHT-LTF符号数。中间前导码指示子字段指示PPDU包括中间前导码子字段时，或者说，当多普勒子字段指示PPDU包括中间前导码子字段时，例如，中间前导码指示子字段指示第一数值(例如1)时，EHT-LTF符号数子字段中的至少一比特作为中间前导码周期子字段指示中间前导码的周期。例如，若EHT-LTF符号数子字段为3比特，中间前导码指示子字段指示PPDU包括中间前导码子字段时，该3比特中的2比特用于指示EHT-LTF的符号数，另外1比特作为中间前导码周期子字段指示中间前导码的周期。
在一些可选的实施例中，中间前导码子字段的周期可以是标准规定的，例如，可以规定中间前导码子字段的周期为20个OFDM符号。这样PPDU可不包括中间前导码周期指示子 字段。这样原用于承载中间前导码周期指示子字段的比特可用于承载其他信息，从而使得PPDU能够承载更多的信息。
下面阐述第一STA和第二STA接收PPDU的数据字段，获得数据字段中的有用信息的实现方式。
在一些实施例中，第一STA为第一类型的STA，如图7B所示的流程示意图，步骤703中，可以包括以下步骤7031和步骤7032，或者说第一STA获得数据字段中的有用的数据信息的具体过程可以包括以下步骤7031或步骤7032。
7031、第一STA识别出U-SIG中的中间前导码指示子字段的数值为第一数值时，忽略中间前导码指示子字段；
第一数值例如可以是默认值1。
本申请实施例中，中间前导码指示子字段指示数据字段包括中间前导码子字段，是通过disregard比特转义指示实现的，第一STA为第一类型的STA时，并不具备读懂disregard比特的能力，那么第一STA仍然会按照原有的disregard比特的含义，忽略该子字段，然后继续接收PPDU。由于第一类型的STA并不能真实地读取中间前导码指示子字段所指示的含义，也不会获取到数据字段是否包括中间前导码子字段的信息，也就不会获取有关中间前导码的周期的信息。
7032、第一STA获取并解析有用信息子字段，以获得有用的数据信息。
第一STA忽略中间前导码指示子字段之后，继续接收PPDU，接收到第一资源单元传输的第一数据字段时，对第一数据字段进行解码，得到该第一数据字段中的有用的数据信息。
具体地，第一STA接收第一数据字段时，从A-MPDU子字段的A-MPDU pre-EOF padding部分(有用信息子字段)获取有用的数据信息。当读取到EOF分隔符时，确定A-MPDU pre-EOF padding部分结束，EOF分隔符之前、服务子字段之后的部分读取到的信息为有用的数据信息。
由此可见，本申请的技术方案，当接收PPDU的第一STA为第一类型的STA时，也能够正常接收数据字段，并获得数据字段中，有用的数据信息。
在另一些实施例中，第一STA为第二类型的STA，如图7C所示的流程示意图，步骤703中，可以包括以下步骤7033和步骤7034，或者说第一STA获得第一数据字段中的有用的数据信息的具体过程可以包括以下步骤7031或步骤70032。
7033、第一STA识别出U-SIG中的中间前导码指示子字段的数值为第一数值时，确定第一数据字段包括中间前导码子字段；
第一数值例如可以是默认值1。
本申请实施例中，中间前导码指示子字段指示数据字段包括中间前导码子字段，是通过disregard比特或validate比特转义指示实现的。第一STA为第二类型的STA时，第一STA具备读懂disregard比特和validate比特的能力。第一STA能够准确读懂中间前导码指示子字段所指示的含义，确定数据字段包括中间前导码子字段。
7034、第一STA根据中间前导码周期指示子字段获取中间前导码的周期；
第一STA确定第一数据字段包括中间前导码之后，则可以继续根据中间前导码周期指示子字段获得中间前导码的周期。
例如，中间前导码周期指示子字段指示中间前导码的周期，是通过disregard比特或 validate比特转义指示实现的，或者说，中间前导码的周期是通过disregard比特或validate比特指示的。这种情况下，第一STA能够准确地读取disregard比特和validate比特，使得第一STA能够准确地读取中间前导码指示子字段指示的含义，获得中间前导码子字段的周期。
又例如，中间前导码周期指示子字段指示中间前导码的周期，是通过NSS子字段中的至少一个比特转义指示来实现的，或者说，中间前导码的周期，是通过NSS子字段中的至少一个比特指示的。这种情况下，第一STA在根据中间前导码指示子字段，确定数据字段包括中间前导码子字段时，则能够确定该NSS子字段中的至少一个比特是用于指示中间前导码的周期，从而能够根据该NSS子字段中的至少一个比特，获取到中间前导码的周期。
再例如，中间前导码周期指示子字段指示中间前导码的周期，是通过EHT-LTF符号数子字段中的至少一个比特转义指示来实现的，或者说，中间前导码的周期，是通过EHT-LTF符号数子字段中的至少一个比特指示的。这种情况下，第一STA在根据中间前导码指示子字段，确定数据字段包括中间前导码子字段时，则能够确定该EHT-LTF符号数子字段中的至少一个比特是用于指示中间前导码的周期，从而能够根据该EHT-LTF符号数子字段中的至少一个比特，获取到中间前导码的周期。
7035、第一STA根据中间前导码的周期，获取位于一个或多个中间前导码子字段中的第一个中间前导码子字段之前的有用信息子字段；
第一STA可根据中间前导码的周期，确定中间前导码子字段出现的位置，从而能够获得数据字段中的有用信息字段。这样可以避免第一STA将中间前导码子字段对应的第1个OFDM符号之后字段误当作有用信息子字段，从而可以保证第一STA获取到的有用的数据信息的准确性。
7036、第一STA获取并解析有用信息子字段，以获得有用的数据信息。
步骤7036的具体实现，可参考上述实施例中步骤7032的相关描述，此处不再详述。
可以看出，当第一STA为第二类型的STA(例如不支持接收中间前导码且支持802.11be R2的STA)时，第一STA虽然不能够根据中间前导码子字段估计信道，但是第一STA能够读懂中间前导码指示子字段，也能够正确地读取中间前导码周期指示子字段，从而可以获得中间前导码的周期，以准确地获取中间前导码对应的第1个OFDM符号之前的有用信息子字段。
在一些实施例中，第二STA是支持接收中间前导码，且能够读懂中间前导码的相关字段的STA(例如支持接收中间前导码，且支持802.11be R2的STA)。PPDU的数据字段包括数据子字段和中间前导码子字段，如图7D所示的流程示意图，关于第二STA接收PPDU的过程，可包括以下步骤7041-步骤7043。
7041、第二STA识别出U-SIG中的中间前导码指示子字段的数值为第一数值时，确定第二数据字段包括中间前导码子字段。
第一数值例如可以是默认值1。
中间前导码指示子字段指示第二数据字段包括中间前导码子字段，是通过disregard比特或validate比特转义指示实现的。第二STA具备读懂disregard比特和validate比特的能力。第二STA能够准确读懂中间前导码指示子字段所指示的含义，确定数据字段包括中间前导码子字段。
7042、第二STA根据中间前导码周期指示子字段获取中间前导码的周期。
第二STA确定数据字段包括中间前导码子字段之后，可以继续根据中间前导码周期指示子字段获得中间前导码的周期。
例如，中间前导码周期指示子字段指示中间前导码的周期，是通过disregard比特或validate比特转义指示实现的，或者说，中间前导码的周期是通过disregard比特或validate比特指示的。这种情况下，第一STA能够准确地读取disregard比特和validate比特，使得第一STA能够准确地读取中间前导码指示子字段指示的含义，获得中间前导码子字段的周期。
又例如，中间前导码周期指示子字段指示中间前导码的周期，是通过NSS子字段中的至少一个比特转义指示来实现的，或者说，中间前导码的周期，是通过NSS子字段中的至少一个比特指示的。这种情况下，第一STA在根据中间前导码指示子字段，确定数据字段包括中间前导码子字段时，则能够确定该NSS子字段中的至少一个比特是用于指示中间前导码的周期，从而能够根据该该NSS子字段中的至少一个比特，获取到中间前导码的周期。
再例如，中间前导码周期指示子字段指示中间前导码的周期，是通过EHT-LTF符号数子字段中的至少一个比特转义指示来实现的，或者说，中间前导码的周期，是通过EHT-LTF符号数子字段中的至少一个比特指示的。这种情况下，第一STA在根据中间前导码指示子字段，确定数据字段包括中间前导码子字段时，则能够确定该EHT-LTF符号数子字段中的至少一个比特是用于指示中间前导码的周期，从而能够根据该EHT-LTF符号数子字段中的至少一个比特，获取到中间前导码的周期。
7043、第二STA根据中间前导码的周期，获取并解析数据子字段。
第二STA能够根据中间前导码的周期，确定数据字段中，中间前导码子字段的位置，从而可以确定数据子字段的位置，以准确地接收并解析数据子字段。
具体地，第二数据字段可包括一个或多个中间前导码子字段。一个或多个中间子字段穿插设置在数据子字段之间。
第二STA在接收第二数据字段时，先接收第1个中间前导码子字段之前的数据子字段，然后接收第1个中间前导码子字段，根据地1个中间前导码子字段进行信道测量，根据信道测量结果，接收第1个中间前导码子字段之后、第2个中间前导码子字段之前的数据子字段，再接收第2个中间前导码子字段，根据第2个中间前导码子字段进行信道测量，据信道测量结果，接收第2个中间前导码子字段之后、第3个中间前导码子字段之前的数据子字段，……，依此类推接收剩余的数据子字段。
这样，第二STA在接收数据子字段的过程中，根据穿插的中间前导码子字段测量信道，能够更准确地获取信道信息，从而能够更准确地接收数据子字段。
应理解，图7D对应的实施例可以单独实施，也可以与图7B或图7C对应的实施例结合实施。
下面阐述关于发送给第一STA的数据字段，AP对数据字段进行编码时，实现有用信息子字段位于中间前导码子字段对应的OFDM符号之前的具体方案。
AP发送PPDU的数据字段时，对编码前的字段添加尾比特(tail bits)和纠错前填充(pre-FEC padding)之后，进行加扰和编码，然后按照中间前导码的周期插入中间前导码子字段，得到数据字段。接收PPDU的设备(例如STA)根据中间前导码子字段进行信道估计，以更新信道信息。接收PPDU的设备，在解码时，对数据字段的除中间前导码子字段之外的部分进行解码。也即是说，接收PPDU的设备，先将数据字段中的中间前导码子字段移除， 再对数据字段的剩余的部分进行解码。
通常采用低密度奇偶校验(low density parity check，LDPC)编码或二进制卷积码(binary convolutional code，BCC)编码对数据字段进行编码。若采用LDPC码进行编码，LDPC码的码长以及码字个数需要根据Data字段编码后比特数决定(number of available bits)。
若第一STA为第一类型的STA，第一STA在接收PPDU时，会将EHT-LTF字段之后，PE之前的OFDM符号全部视为数据字段。AP在生成PPDU时，为了保证发送给每个STA的PPDU的长度股相同，在对数据字段添加纠错前填充(pre-FEC padding)时，需要将中间前导码的长度考虑在内。
在一些实施例中，对数据字段采用LDPC编码，装载有用信息的码字在第1个中间前导码子字段之前结束。这样能够保证第一STA能够对数据字段能够正确解码获得有用信息，而且能够避免因有用信息子字段过长而导致多普勒效应严重影响数据字段的接收的准确度。
在另一些实施例中，对数据字段采用BCC编码，装载有用信息的有用信息子字段的符号数小于中间前导码的周期。
具体地，下面详细说明AP向多个STA发送PPDU，多个STA包括第一STA和第二STA，第一STA为第一类型的STA时，AP向第一STA发送的PPDU的数据字段中的pre-FEC padding添加流程包括以下步骤：
1、计算AP发送给各个STA的PPDU的数据字段编码的初始符号数N SYM,init,u与初始pre-FEC padding参数a init.u。其中，下标u＝0,1，…,N PPDU,total-1。N PPDU,total表示AP发送的PPDU的总数。本申请实施例以PPDU不采用空时编码(space time block code，STBC)为例进行说明。
2、若接收端设备包括多个支持接收中间前导码的STA，确定包含中间前导码的一个或多个PPDU中，编码数据包的持续时间最长
Figure PCTCN2021123193-appb-000004
的PPDU的索引，得到所有包含中间前导码的PPDU的初始符号数N SYM,init以及初始pre-FEC padding参数a init。
其中，N SYM,init＝N SYM,init,umax；
Figure PCTCN2021123193-appb-000005
Figure PCTCN2021123193-appb-000006
3、计算包含中间前导码的PPDU中的数据字段的最终符号数以及pre-FEC padding参数。
若发送给多个STA的PPDU的数据字段中，存在数据字段采用LDPC码进行编码，且出现计算得到编码所需打孔比特数过多需要延长编码后比特长度以保证纠错性能的情况，则需将发送给各个STA的PPDU(包括发送给R1设备的PPDU)中EHT-SIG或者HE-SIG-A字段中的LDPC Extra Symbol Segment字段设为1，并更新符号数与pre-FEC padding参数a init如下：
Figure PCTCN2021123193-appb-000007
若发送给第一STA的数据字段均采用LDPC编码，则将所有PPDU中EHT-SIG或者 HE-SIG-A字段中的LDPC Extra Symbol Segment字段设为1，并更新符号数与pre-FEC padding参数a init如下：
Figure PCTCN2021123193-appb-000008
若计算结果无需延长编码后比特长度，且发送给R1设备的PPDU中Data字段采用BCC编码，则将所有PPDU中EHT-SIG或者HE-SIG-A字段中的LDPC Extra Symbol Segment字段设为0，并更新符号数与pre-FEC padding参数a init如下：
N SYM＝N SYM,initand a＝a init。
将EHT-SIG或者HE-SIG-A字段中的Pre-FEC Padding字段设为值a。
若计算结果无需延长编码后比特长度，且发送给R1设备的PPDU中Data字段采用BCC编码，则将所有PPDU中EHT-SIG或者HE-SIG-A字段中的LDPC Extra Symbol Segment字段设为0，并更新符号数与pre-FEC padding参数a init如下：
N SYM＝N SYM,initand a＝a init。
将EHT-SIG或者HE-SIG-A字段中的Pre-FEC Padding字段设为值a。
4、计算插入中间前导码子字段的周期的个数N MA，并计算发送给第一STA的PPDU中数据字段的符号数N SYM,R1以及pre-FEC padding参数a init：
Figure PCTCN2021123193-appb-000009
N SYM,R1＝N SYM+N MA·N EHT–LTF；
a R1＝a。
其中，N EHT–LTF代表EHT-LTF字段中的4x符号数。
5、若数据字段采用BCC编码，则装载有用信息的字段(有用信息子字段)的符号数需满足：
Figure PCTCN2021123193-appb-000010
其中，APEP_LENGTH为TXVECTOR中参数APEP_LENGTH，表示有用信息子字段的字节数；M MA为中间前导码子字段的周期符号数；N DBPS为每个符号包含的数据比特数；N Service为PPDU中的服务子字段比特数，值为常数16；N tail为尾比特个数只在BCC中存在。
有用信息子字段的字节数的限制条件如下：
Figure PCTCN2021123193-appb-000011
6、若数据字段采用LDPC编码，则先根据数据比特长度N pld和可以传递的比特数N avbits，确定LDPC码的码长L LDPC和总共所需的码字N CW
N pla＝(N SYM,init+N MA·N EHT–LTF-1)·N DBPS+N DBPS,laSt，
N avbits＝(N SYM,R1-1)·N CBPS+N CBPS,last；
其中，
N CBPS＝N DBPS/R代表每个符号包含的编码后比特数，R为码率；
N DBPS,last和N CBPS,last代表最后一个符号中数据比特和编码后比特个数。
PPDU的编码参数如表2所示。
表2
Figure PCTCN2021123193-appb-000012
LDPC码在经过截短(shortening)，打孔(puncturing)或重复(repeating)后，最终得到的所有码字的码长L LDPC,avbitS满足
Figure PCTCN2021123193-appb-000013
这样能够保证编码后的码长不能超出周期的最后一个符号，但是能包括有用信息子字段。为考虑极端情况，假设所有码字的码取上限
Figure PCTCN2021123193-appb-000014
以及每个码字中包含的数据比特数L LDPC,pld满足
Figure PCTCN2021123193-appb-000015
由于头部码字会多截短一个比特，因此此处假设所有码字的码取下限
Figure PCTCN2021123193-appb-000016
为保证接收端的STA正确解码，装载有用信息的码字所包含的编码后比特数N avbits,info需满足：N avbits,info≤N CW,info·L LDPC,avbits≤M MAN CBPS。
其中，
Figure PCTCN2021123193-appb-000017
代表装载有用信息的码字个数。
最终得到有用信息字节数的限制条件如下：
Figure PCTCN2021123193-appb-000018
7、计算发送给第一STA的PPDU的pre-FEC padding的长度
N PAD,Pre–FEC＝(N SYM,R1-1)·N DBPS+N DBPS,last-8·APEP_LENGTH-N service-N tail,
其中，N DBPS,last代表最后一个符号中的数据比特数，由pre-FEC padding factor a和N DBPS共同决定。
8、在MAC层和PHY层分别添加如下所示pre-FEC pad bits
Figure PCTCN2021123193-appb-000019
N PAD,Pre–FEC,PHY＝N PAD,Pre–FECmod 8。
第一类型的第一STA会在读取到Data字段A-MPDU中的EOF分隔符后确定有用信息子字段的长度，并忽略剩余的填充(padding)子字段。
可选的，本申请实施例中，第一STA为第一类型的STA时，发送给第二STA的PPDU的数据字段中的中间前导码子字段为4x EHT-LTF。这样能够避免第一STA在接收数据字段时，在中间前导码子字段对应的OFDM符号开始之后，继续解调数据字段中的信息，造成误读。
若第一STA为第二类型的STA，第一STA能够读懂中间前导码指示子字段，也能获得中间前导码的周期。如果第一STA在接收数据字段时，不具备将中间前导码子字段从数据字段中去除再进行解码的能力，则AP向第一STA发送的PPDU的数据字段中的pre-FEC padding添加流程，与上述第一STA为第一类型的STA时的流程可以是相同的。如果具备将中间前导码子字段从数据字段中去除再进行解码的能力，但是无法根据中间前导码子字段测量信道，AP向第一STA发送的PPDU的数据字段的结构，可以与AP向第二STA发送的PPDU的数据字段的结构相同。
如图10所示的结构示意图，本申请实施例提供一种PPDU的传输装置。该传输装置可作为PPDU的发送端设备，或者部署在PPDU的发送端设备。该发送端设备可以是接入点，也可以是站点。传输装置1000包括：
处理单元1001，用于生成物理层协议数据单元PPDU，所述PPDU包括数据字段；
发送单元1002，用于向第一站点和第二站点发送所述PPDU，所述第一站点为不支持接收中间前导码的站点，所述第二站点为支持接收中间前导码的站点；
其中，所述第二站点被分配的第二资源单元传输的第二数据字段包括中间前导码子字段，所述第一站点被分配的第一资源单元传输的第一数据字段包括有用信息子字段，所述有用信息子字段包括有用的数据信息。
有用信息子字段符合以下至少一种：
所述有用信息子字段位于所述中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置在中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置，不晚于中间前导码子字段对应的第1个OFDM符号。
申请实施例的技术方案，在多普勒场景下，发送端同时向不支持接收中间前导码的第一站点和支持接收中间前导码的第二站点发送PPDU，而且不支持接收中间前导码的第一站点接收的第一数据字段中的有用信息子字段位于中间前导码子字段对应的第1个OFDM符号之 前。这样能够资源利用效率，而且能够避免在多普勒场景下，因第一数据字段中的承载有有用信息的部分过长，但是第一站点却因为无法根据中间前导码实时估计信道而导致对数据字段的读取有误差，有助于使得不支持接收中间前导码的第一站点能够准确地获取数据字段中的有用的数据信息。
在一些实施方式中，所述PPDU还包括通用信令字段U-SIG，所述U-SIG包括中间前导码指示子字段，所述中间前导码指示子字段指示所述PPDU的数据字段包括中间前导码子字段。中间前导码指示子字段又可称作多普勒指示子字段。本申请对字段的名称不做限定。
例如，对于第一类型的站点，可利用U-SIG中的至少一个disregard比特来承载中间前导码指示子字段。或者说，U-SIG中的至少一个disregard比特可用于作为中间前导码指示子字段。这样，第一类型的第一站点在读取disregard比特时，会直接忽略。利用disregard比特转义指示中间前导码，能够保证第一类型的站点正常的接收数据字段。
又例如，对于第二类型的站点，可利用U-SIG中的至少一个disregard比特承载中间前导码指示子字段，也可以利用U-SIG中的至少一个validate比特来承载中间前导码指示子字段。换句话说，U-SIG中的至少一个disregard比特或至少一个validate比特可用于作为中间前导码指示子字段。可以理解，第二类型的站点能够读懂disregard比特和validate比特，那么利用disregard比特或validate比特承载中间前导码指示子字段，接收PPDU的第一站点是可以读懂中间前导码指示子字段所指示的含义的，从而能够实现准地接收数据字段中的有用信息子字段，已获得有用信息。
第二站点能够根据该中间前导码指示子字段，确定数据字段中是否存在中间前导码子字段，从而能够更准确地读取数据字段。
在一些实施方式中，所述PPDU还包括极高吞吐量-信令字段EHT-SIG，所述U-SIG或EHT-SIG包括中间前导码周期子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期。这样，第二站点能够根据该中间前导码周期指示子字段获得中间前导码子字段的周期，获得中间前导码子字段在数据字段中的位置，从而能够实现从数据字段中准确地读取除中间前导码子字段以外的部分，以获得有用的数据信息。
在所述中间前导码指示子字段的值为第一数值时，指示所述PPDU的数据字段包括中间前导码子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期；
在所述中间前导码指示子字段的值为第二数值时，所述中间前导码指示子字段指示所述PPDU的数据字段不包括中间前导码子字段，所述中间前导码周期指示子字段指示空间流数、极高吞吐量-长训练序列EHT-LTF的符号数、不理会disregard或证实validate。
这样，能够实现同一比特承载的字段，在中间前导码指示子字段的值不同时，指示不同的含义，充分利用了传输资源，提升了传输资源利用效率。
如图11所示的结构示意图，本申请实施例提供一种PPDU的传输装置。该传输装置可作为PPDU的接收端设备，或者部署在PPDU的接收端设备。该接收端设备可以是站点，也可以是接入点。该接收端设备例如可以是上述实施例中的第一站点。传输装置1100包括：
接收单元1101，用于接收PPDU所述PPDU包括数据字段，
处理单元1102，用于解析所述PPDU以获得所述有用的数据信息；
其中，有用信息子字段符合以下至少一项：
所述有用信息子字段位于所述中间前导码子字段对应的第1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置在中间前导码子字段对应的第 1个OFDM符号之前；或者
第一数据字段还包括填充子字段，填充子字段的起始位置，不晚于中间前导码子字段对应的第1个OFDM符号。
本申请实施例的技术方案，能够避免在多普勒场景下，因第一数据字段中的承载有有用信息的部分过长，但是不支持接收中间前导码的站点却因为无法根据中间前导码实时估计信道而导致对数据字段的读取有误差，有助于使得不支持接收中间前导码的站点能够准确地获取数据字段中的有用的数据信息。
在一些实施方式中，所述PPDU还包括通用信令字段U-SIG，所述U-SIG包括中间前导码指示子字段，所述中间前导码指示子字段指示所述PPDU的数据字段包括中间前导码子字段。中间前导码指示子字段又可称作多普勒指示子字段。本申请对字段的名称不做限定。中间前导码指示子字段的相关描述可参考第一方面的传输方法中提供的中间前导码指示子字段。
在一些实施方式中，所述PPDU还包括极高吞吐量-信令字段EHT-SIG，所述U-SIG或EHT-SIG包括中间前导码周期子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期。中间前导码周期指示子字段的相关描述可参考第一方面的传输方法中提供的中间前导码周期指示子字段。
在一些实施方式中，该传输装置为第一类型的站点，或者用于第一类型的站点，所述解析所述PPDU以获得所述有用的数据信息方面，处理器具体用于：识别出所述U-SIG中的所述中间前导码指示子字段的数值为所述第一数值时，忽略所述中间前导码指示子字段；获取并解析所述有用信息子字段，以获得所述有用的数据信息。
中间前导码指示子字段指示数据字段包括中间前导码子字段，是通过disregard比特转义指示实现的，第一站点为第一类型的站点时，并不具备读懂disregard比特的能力，那么第一站点仍然会按照原有的disregard比特的含义，忽略该子字段，然后继续接收PPDU接收到第一资源单元传输的第一数据字段时，对第一数据字段进行解码，得到该第一数据字段中的有用的数据信息。
在另一些实施方式中，该传输装置为第二类型的站点，或者用于第二类型的站点，所述解析所述PPDU以获得所述有用的数据信息方面，处理器具体用于：识别出所述U-SIG中的所述中间前导码指示子字段的数值为所述第一数值时，确定所述数据字段包括中间前导码子字段；根据所述中间前导码周期指示子字段获取所述中间前导码的周期；根据所述中间前导码的周期，获取位于所述中间前导码子字段对应的第1个OFDM符号之前的有用信息子字段；获取并解析所述有用信息子字段，以获得所述有用的数据信息。
中间前导码指示子字段和中间前导码周期指示子字段，是通过disregard比特或validate比特转义指示实现指示的。第一站点为第二类型的站点时，第一站点具备读懂disregard比特和validate比特的能力。第一站点能够准确读懂中间前导码指示子字段以及中间前导码周期指示子字段所指示的含义，确定数据字段包括中间前导码子字段，以及中间前导码子字段的周期，从而准确地获取中间前导码对应的第1个OFDM符号之前的有用信息子字段。
如图12所示的结构示意图，本申请实施例提供一种PPDU的传输装置。该传输装置可作为PPDU的接收端设备，或者部署在PPDU的接收端设备。该接收端设备可以是站点，也可以是接入点。该接收端设备例如可以是上述实施例中的第二站点。传输装置1200包括：
接收单元1201，用于接收PPDU，所述PPDU包括数据字段，所述数据字段包括数据子字段和一个或多个间隔设置的中间前导码子字段，所述数据子字段所述中间前导码子字段间 隔为至少两段；所述数据子字段包括有用的数据信息。
处理单元1202，用于解析所述PPDU以获得所述有用的数据信息。
这样的方案，在数据字段部分穿插设置中间前导码子字段，使得接收端设备在接收数据字段时，能够根据穿插设置的中间前导码对信道进行估计，及时获取最新的信道信息，从而能够使得接收端设备更好地接收数据字段。
应理解，上述PPDU的传输方法实施例的相关描述也适用于本申请实施例的PPDU的传输装置，为避免冗余，此处不再重复描述。
上述PPDU的传输装置中的接收单元，可通过上述PPDU的传输装置200的接收器实现，上述PPDU的传输装置中的发送单元，可通过上述PPDU的传输装置200的发送器实现。上述PPDU的传输装置中的处理单元，可通过上述PPDU的传输装置200的处理器201实现。
虽然本申请实施例主要以部署IEEE 802.11的网络为例进行说明，本领域技术人员容易理解，本申请涉及的各个方面可以扩展到采用各种标准或协议的其它网络，例如，BLUETOOTH(蓝牙),高性能无线LAN(high performance radio LAN，HIPERLAN)(一种与IEEE 802.11标准类似的无线标准，主要在欧洲使用)以及广域网(WAN)、无线局域网(wireless local area network,WLAN)、个人区域网(personal area network,PAN)或其它现在已知或以后发展起来的网络。因此，无论使用的覆盖范围和无线接入协议如何，本申请提供的各种方面可以适用于任何合适的无线网络。
还应理解，本文中涉及的第一、第二、第三、第四以及各种数字编号仅为描述方便进行的区分，并不用来限制本申请的范围。
应理解，本文中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部 件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
本申请实施例方法中的步骤可以根据实际需要进行顺序调整、合并和删减。
本申请实施例装置中的模块可以根据实际需要进行合并、划分和删减。
以上所述，以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的范围。

Claims (12)

  1. 一种物理层协议数据单元PPDU的传输方法，其特征在于，所述方法包括：
    生成PPDU，所述PPDU包括数据字段；
    向第一站点和第二站点发送所述PPDU，所述第一站点为不支持接收中间前导码的站点，所述第二站点为支持接收中间前导码的站点；
    其中，所述第二站点被分配的第二资源单元传输的第二数据字段包括中间前导码子字段，所述第一站点被分配的第一资源单元传输的第一数据字段包括有用信息子字段，所述有用信息子字段包括有用的数据信息，所述有用信息子字段位于所述中间前导码子字段对应的第1个OFDM符号之前。
  2. 根据权利要求1所述的传输方法，其特征在于，所述PPDU还包括通用信令字段U-SIG，所述U-SIG包括中间前导码指示子字段，所述中间前导码指示子字段指示所述PPDU的数据字段包括中间前导码子字段。
  3. 根据权利要求2所述的方法，其特征在于，所述PPDU还包括极高吞吐量-信令字段EHT-SIG，所述U-SIG或EHT-SIG包括中间前导码周期子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期。
  4. 根据权利要求3所述的方法，其特征在于，所述中间前导码指示子字段的值为第一数值时，所述中间前导码指示子字段指示所述PPDU的数据字段包括中间前导码子字段，所述中间前导码周期指示子字段指示所述中间前导码的周期；
    所述中间前导码指示子字段的值为第二数值时，所述中间前导码指示子字段指示所述PPDU的数据字段不包括中间前导码子字段，所述中间前导码周期指示子字段指示空间流数、极高吞吐量-长训练序列EHT-LTF的符号数、不理会disregard或证实validate。
  5. 根据权利要求1-4任一项所述的方法，其特征在于，所述第一数据字段还包括填充子字段，所述填充子字段的起始位置在所述中间前导码子字段对应的第1个OFDM符号之前。
  6. 一种物理层协议数据单元PPDU的传输方法，其特征在于，所述方法包括：
    接收PPDU，所述PPDU包括数据字段，所述数据字段包括有用信息子字段和中间前导码子字段，所述有用信息子字段位于所述中间前导码子字段中对应的第1个OFDM符号之前，所述有用信息子字段包括有用的数据信息；
    解析所述PPDU以获得所述有用的数据信息。
  7. 根据权利要求6所述的传输方法，其特征在于，所述方法用于第一类型的站点，所述解析所述PPDU以获得所述有用的数据信息包括：
    识别出所述U-SIG中的所述中间前导码指示子字段的数值为所述第一数值时，忽略所述中间前导码指示子字段；
    获取并解析所述有用信息子字段，以获得所述有用的数据信息。
  8. 根据权利要求6所述的传输方法，其特征在于，所述方法用于第二类型的站点，所述解析所述PPDU以获得所述有用的数据信息包括：
    识别出所述U-SIG中的所述中间前导码指示子字段的数值为所述第一数值时，确定所述数据字段包括中间前导码子字段；
    根据所述中间前导码周期指示子字段获取所述中间前导码的周期；
    根据所述中间前导码的周期，获取位于所述中间前导码子字段对应的第1个OFDM符号之前的有用信息子字段；
    获取并解析所述有用信息子字段，以获得所述有用的数据信息。
  9. 根据权利要求6-8任一项所述的方法，其特征在于，所述数据字段还包括填充子字段，所述填充子字段的起始位置在所述第一个中间前导码子字段之前。
  10. 一种PPDU的传输装置，其特征在于，包括处理器，所述处理器与存储器耦合，所述存储器用于存储计算机指令，所述处理器执行该计算机指令，使得所述传输装置执行权利要求1-9任一项所述的方法。
  11. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质中存储有计算机指令，所述计算机指令指示通信装置执行权利要求1-9任一项所述的方法。
  12. 一种包含指令的计算机程序产品，当所述指令在计算机上运行时，使得所述计算机执行权利要求1-9任一项所述的方法。
PCT/CN2021/123193 2021-01-04 2021-10-12 Ppdu的传输方法及相关装置 WO2022142577A1 (zh)

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CN109428704A (zh) * 2017-08-31 2019-03-05 华为技术有限公司 一种中间前导码指示、接收方法及装置
CN109964442A (zh) * 2016-11-20 2019-07-02 高通股份有限公司 指示中导码的存在性
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CN109964442A (zh) * 2016-11-20 2019-07-02 高通股份有限公司 指示中导码的存在性
CN108737054A (zh) * 2017-04-21 2018-11-02 联发科技股份有限公司 无线通信方法和无线通信设备
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