PPDU transmission method and related device

Abstract

To provide a PPDU transmission method and a related device.SOLUTION: A method includes: generating a PPDU, the PPDU including a universal signal field U-SIG, the U-SIG including a subfield indicating that the PPDU is a null data packet NDP; and transmitting the PPDU. Thus, Bfee receiving the NDP can identify the NDP earlier. This helps to improve efficiency of Bfee reading the NDP. The PPDU is the NDP used for 802.11ax or later standards. In a scenario where wireless communication is performed using 802.11ax or later standards (for example, 802.11be), Bfee can perform channel estimation on the basis of the NDP.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] This application claims priority to Chinese Patent Application No. 202010506948.X, entitled “PPDU TRANSMISSION METHOD AND RELATED APPARATUS,” filed with the State Intellectual Property Office of the People's Republic of China on June 5, 2020, which application is hereby incorporated by reference in its entirety. This application relates to the field of wireless local area network technology, and in particular to a PPDU transmission method and related device. [Background technology]

[0002] In wireless systems, such as wireless local area networks (WLANs), access points (APs) and stations (STAs) need to acquire channel state information in advance to implement functions such as beamforming (BF), rate control, and resource allocation. In WLANs, the procedure of acquiring channel state information is called channel sounding. In the related art, in the process of an AP performing channel sounding, the AP first transmits a null data packet announcement (NDPA) frame to notify a STA that it needs to perform channel sounding. Then, after a short interframe space (SIFS), the AP transmits a null data packet (NDP) without a data field. The STA uses the NDP to perform channel estimation, and then uses a beamforming report (BF report) frame to feed back channel state information (CSI). Then, the AP transmits a physical layer protocol data unit (PHY protocol data unit, PPDU) based on the channel state information fed back by the STA.

[0003] The PPDU in the 802.11ax standard is called a high efficiency (HE) PPDU, while the PPDU in the 802.11be standard is called an extremely high throughput (EHT) PPDU.

[0004] However, in the related art, only the structure of the HE NDP for the HE PPDU is provided, and the structure of the EHT NDP is not designed. Summary of the Invention

[0005] The implementation of this application provides a PPDU transmission method and related device in a scenario where 802.11ax or later standards (e.g., 802.11be) are used for wireless communication, such that an AP or STA can perform channel estimation by obtaining channel state information using NDP.

[0006] According to a first aspect, the application provides a PPDU transmission method, the method including: generating a physical layer protocol data unit PPDU, the PPDU including a universal signal field U-SIG, the U-SIG including a subfield indicating that the PPDU is a null data packet NDP; and transmitting the PPDU.

[0007] This PPDU is the NDP used in 802.11ax and later standards and does not contain a data field, and is used by Bfee to perform channel estimation.

[0008] A device that transmits the NDP may be understood as a beamformer (Bfer). A device that receives the NDP and performs channel estimation based on the NDP may be understood as a beamformee (Bfee). Bfer may be an AP or a STA. Bfee may be an STA or an AP.

[0009] In one implementation of this application, the U-SIG of the PPDU includes a subfield indicating that the PPDU is an NDP, and the device receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG indicating that the PPDU is an NDP, so that Bfee can prepare the procedure of calculating channel state information in advance to obtain a longer processing time, and does not need to calculate that the length of the data part of the PPDU is 0 and then determine that the PPDU is an NDP. The NDP helps improve the efficiency of receiving the NDP.

[0010] Optionally, the subfield indicating that the PPDU is an NDP is the NDP indication subfield, the PPDU format subfield, or the subfield indicating the number of EHT-SIG symbols in the U-SIG.

[0011] In some implementations, the PPDU further includes an Ultra High Throughput-Short Training field EHT-STF adjacent to and following the U-SIG. The EHT-STF immediately follows the U-SIG. The NDP does not include the EHT-SIG. Thus, the structure of the NDP provided in this application is used in the EHT NDP. This helps to achieve alignment between symbols of the NDP transmitted on all channels when hybrid transmission is performed on the EHT NDP and the HE NDP in an aggregated PPDU transmission scenario, so that out-of-band interference between different frequency bands can be avoided.

[0012] The NDP does not include the EHT-SIG. The U-SIG does not need to indicate the number of EHT-SIG symbols or the modulation and coding scheme (MCS), nor does it need to indicate any coding-related indications, such as the low density parity check (LDPC) additional symbol segment indication. The packet extension indication may use a fixed value and therefore does not need to be indicated.

[0013] In this way, the U-SIG may not include the subfield indicating the number of EHT-SIG symbols, the MCS subfield, the LDPC additional symbol segment subfield, or the packet extension disambiguity subfield. The bits used to carry these fields in the U-SIG of the PPDU including the data field may be used to carry other information in the U-SIG of the NDP, or the bits used to carry these fields may be used to carry other fields. For example, the bits used to carry these fields may be used to carry the subfield indicating the number of EHT-LTF symbols, allowing the U-SIG of the NDP to include more information.

[0014] It should be understood that in some optional implementations, based on the structure of the NDP shown in Figure 9, the U-SIG may instead include a subfield indicating the number of EHT-SIG symbols. The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is a default value, and indicates that the PPDU is an NDP. The subfield indicating the number of EHT-SIG symbols may be, but is not limited to, a subfield indicating a number of EHT-SIG symbols / MU-MIMO users, or an EHT-SIG symbol number subfield used to indicate only the number of EHT-SIG symbols.

[0015] Optionally, the U-SIG further includes a Number of Spatial Streams subfield and / or a subfield indicating the number of EHT-LTF symbols of the very high throughput-long training field, where the Number of Spatial Streams subfield and / or the subfield indicating the number of EHT-LTF symbols indicate the number of spatial streams and the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols can be, for example, the Number of EHT-LTF Symbols-Midamble Periodicity-Doppler subfield, or can be the Number of EHT-LTF Symbols subfield indicating the number of EHT-LTF symbols individually.

[0016] According to a second aspect, an implementation of the present application further provides a PPDU transmission method, the method including: generating a PPDU, the PPDU being an NDP, the PPDU including an ultra-high throughput-signal field EHT-SIG, the number of EHT-SIG symbols being 1, and the EHT-SIG being modulated using BPSK and a code rate of 1 / 2; and transmitting the PPDU.

[0017] This PPDU is the NDP used in 802.11ax and later standards and does not contain a data field. This NDP is used by Bfee to perform channel sounding.

[0018] In the technical solution of this application, the number of EHT-SIG symbols in the NDP is 1. The structure of the NDP can reduce the number of EHT-SIG symbols, and therefore reduce the overhead required to transmit the NDP.

[0019] In some implementations, the PPDU further includes a universal signal field U-SIG, which includes a subfield indicating the number of EHT-SIG symbols, where the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is some value greater than or equal to 1. The subfield indicating the number of EHT-SIG symbols may be, but is not limited to, a subfield indicating the number of EHT-SIG symbols or MU-MIMO users, or an EHT-SIG symbol number subfield used to indicate only the number of EHT-SIG symbols.

[0020] The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and Bfee receiving the NDP can calculate that the length of the data field in the PPDU is 0 and determine that the PPDU is an NDP. The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is greater than 1, and Bfee can calculate that the length of the data field in the PPDU is less than 0 and determine that the PPDU is an NDP.

[0021] In some implementations, the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and the U-SIG further includes a modulation and coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0022] Thus, Bfee can identify that a PPDU is an NDP without calculating the number of symbols in the data field. Thus, Bfee can prepare the procedure of calculating channel state information in advance to obtain more processing time, and does not need to calculate that the length of the data part of the PPDU is 0 and then determine that the PPDU is an NDP. The NDP helps Bfee improve the efficiency of reading the NDP.

[0023] In some implementations, the NDP indication subfield or the PPDU format subfield in the U-SIG indicates that the PPDU is in uncompressed mode. When the PPDU is in uncompressed mode, the subfield indicating the number of EHT-SIG symbols or MU-MIMO users in the U-SIG indicates the number of EHT-SIG symbols. Thus, the subfield indicating the number of EHT-SIG symbols or MU-MIMO users may indicate that the number of EHT-SIG symbols is 1.

[0024] In some implementations, the number of space-time streams subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG indicate the number of space-time streams and the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols may be, for example, the Number of EHT-LTF Symbols, Midamble Periodicity, and Doppler subfields, or may be the Number of EHT-LTF Symbols subfield indicating the number of EHT-LTF symbols separately.

[0025] According to a third aspect, the application further provides a PPDU transmission method, the method including: generating a PPDU, the PPDU being an NDP, the PPDU including an EHT-SIG, the EHT-SIG including an AID subfield indicating an association identifier AID, the AID being used to indicate information about a user of the NDP; and transmitting the PPDU.

[0026] Thus, Bfee can determine information about the users of the NDP based on the AID in the EHT-SIG of the NDP, and thus can accurately determine whether the users are those for which Bfee needs to perform channel sounding and feed back beamforming reports.

[0027] The PPDU in this solution is the NDP used in 802.11ax and later standards, which does not contain a data field, and is used by Bfee to perform channel sounding.

[0028] In some implementations, when the user of the NDP is a station, the AID indicated by the AID subfield is the AID of the station. Thus, the station corresponding to the AID can determine based on the AID in the NDP that the station is a station that needs to perform channel sounding and feed back a beamforming report based on the channel sounding result.

[0029] In this way, even if a station fails to read the user field containing the station's AID because the station does not read the NDPA frame correctly, the station can determine based on the NDP that the station is a station that needs to perform channel sounding and feed back a beamforming report based on the channel sounding result, thus improving the success rate of Bfer obtaining the beamforming report.

[0030] Also, after receiving the NDP, if a device that does not match the AID indicated by the AID subfield reads that the AID indicated by the AID subfield does not match the AID of the device, the device will not continue to receive the NDP, thereby reducing the power consumption of the device that does not match the AID indicated by the AID subfield.

[0031] In some implementations, when the users of the NDP are multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted through broadcast. In this implementation, the EHT-SIG of the NDPA frame transmitted before the NDP includes a multiple stations field, and the AID subfield in the multiple stations field indicates the AID of the station that needs to perform channel sounding and feedback the beamforming report. Thus, the station receives the NDP and determines that the users of the NDP are multiple stations based on the AID subfield of the NDP being 0. Thus, all stations that receive the NDP, or the stations that correspond to the AID indicated by the user field in the NDPA frame, continue to receive the NDP, obtain channel state information based on the NDP, and feedback the beamforming report.

[0032] In some implementations, when the user of the NDP is an access point, the AID indicated by the AID subfield is a default value. The default value can be announced by the AP through broadcast, or can be a fixed value pre-set in a standard, such as 2045. It should be understood that the default value can be another value instead.

[0033] In some implementations, the PPDU further includes a U-SIG, which includes a format subfield and / or a compressed subfield, and the format subfield or the compressed subfield indicates that the PPDU is an NDP. Thus, after identifying the PPDU, Bfee can identify that the PPDU is an NDP based on the format subfield or the compressed subfield. Thus, before the number of symbols in the data field of the PPDU is calculated to be 0, the PPDU can be identified as an NDP, and the PPDU is read based on the format of the NDP, so that Bfee can prepare a procedure for calculating channel state information in advance, obtain a longer processing time, and improve the efficiency of reading the NDP.

[0034] In some implementations, the PPDU further includes a U-SIG and an EHT-LTF, and the U-SIG includes a space-time stream number subfield indicating the number of space-time streams, and the number of EHT-LTFs is greater than the number of space-time streams. Thus, in an aggregated PPDU transmission scenario, when multiple NDPs with the same structure are transmitted on different channels, the number of EHT-LTF symbols of the NDPs transmitted on the channels can be the same even if the spatial streams on the channels are different. This helps align the symbols of the fields of the NDPs to avoid out-of-band interference between different frequency bands.

[0035] According to a fourth aspect, the application further provides a PPDU transmission method, the method including: receiving a PPDU, the PPDU being an NDP, the PPDU including a universal signal field U-SIG, the U-SIG including a subfield indicating that the PPDU is a null data packet NDP; and performing channel estimation using the NDP.

[0036] This PPDU is the NDP used in 802.11ax and later standards and does not contain a data field. This NDP is used by Bfee to perform channel sounding.

[0037] In one implementation of this application, the U-SIG of the PPDU includes a subfield indicating that the PPDU is an NDP, and the device receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG indicating that the PPDU is an NDP, so that Bfee can prepare the procedure of calculating channel state information in advance to obtain a longer processing time, and does not need to calculate that the length of the data part of the PPDU is 0 and then determine that the PPDU is an NDP. The NDP helps improve the efficiency of receiving the NDP.

[0038] Optionally, the subfield indicating that the PPDU is an NDP is the NDP indication subfield, the PPDU format subfield, or the subfield indicating the number of EHT-SIG symbols in the U-SIG.

[0039] In some implementations, the PPDU further includes an Ultra High Throughput-Short Training field EHT-STF adjacent to and following the U-SIG. The EHT-STF immediately follows the U-SIG. The NDP does not include the EHT-SIG. Thus, the structure of the NDP provided in this application is used in the EHT NDP. This helps to achieve alignment between symbols of the NDP transmitted on all channels when hybrid transmission is performed on the EHT NDP and the HE NDP in an aggregated PPDU transmission scenario, so that out-of-band interference between different frequency bands can be avoided.

[0040] The NDP does not include the EHT-SIG. The U-SIG does not need to indicate the number of EHT-SIG symbols or the MCS, and does not need to indicate coding-related indications, such as the LDPC additional symbol segment indication. The packet extension indication can use a fixed value and therefore does not need to be indicated.

[0041] In this way, the U-SIG may not include the subfield indicating the number of EHT-SIG symbols, the MCS subfield, the LDPC additional symbol segment subfield, or the packet extension disambiguity subfield. The bits used to carry these fields in the U-SIG of the PPDU that includes the data field may be used to carry other information in the U-SIG of the NDP, or the bits used to carry these fields may be used to carry other fields. For example, the bits used to carry these fields may be used to carry the subfield indicating the number of EHT-LTF symbols, allowing the U-SIG of the NDP to include more information.

[0042] It should be understood that in some optional implementations, based on the structure of the NDP shown in Figure 9, the U-SIG may instead include a subfield indicating the number of EHT-SIG symbols. The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is a default value to indicate that the PPDU is an NDP. The subfield indicating the number of EHT-SIG symbols may be, but is not limited to, a subfield indicating a number of EHT-SIG symbols / MU-MIMO users, or an EHT-SIG symbol number subfield used to indicate only the number of EHT-SIG symbols.

[0043] Optionally, the U-SIG further includes a Number of Spatial Streams subfield and / or a subfield indicating the number of EHT-LTF symbols of the very high throughput-long training field, where the Number of Spatial Streams subfield and / or the subfield indicating the number of EHT-LTF symbols indicate the number of spatial streams and the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols can be, for example, the Number of EHT-LTF Symbols-Midamble Periodicity-Doppler subfield, or can be the Number of EHT-LTF Symbols subfield indicating the number of EHT-LTF symbols individually.

[0044] According to a fifth aspect, the application further provides a PPDU transmission method, the method including: receiving a PPDU, the PPDU being an NDP, the PPDU including an ultra-high throughput-signal field EHT-SIG, the number of EHT-SIG symbols being 1, the EHT-SIG being modulated using BPSK and a code rate of 1 / 2; and performing channel estimation using the NDP.

[0045] This PPDU is the NDP used in 802.11ax and later standards and does not contain a data field. This NDP is used by Bfee to perform channel sounding.

[0046] In the technical solution of this application, the number of EHT-SIG symbols in the NDP is 1. The structure of the NDP can reduce the number of EHT-SIG symbols, and therefore reduce the overhead required to transmit the NDP.

[0047] In some implementations, the PPDU further includes a universal signal field U-SIG, which includes a subfield indicating the number of EHT-SIG symbols, where the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is some value greater than or equal to 1. The subfield indicating the number of EHT-SIG symbols may be, but is not limited to, a subfield indicating the number of EHT-SIG symbols or MU-MIMO users, or an EHT-SIG symbol number subfield used only to indicate the number of EHT-SIG symbols.

[0048] The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and Bfee receiving the NDP can calculate that the length of the data field in the PPDU is 0 and determine that the PPDU is an NDP. The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is greater than 1, and Bfee can calculate that the length of the data field in the PPDU is less than 0 and determine that the PPDU is an NDP.

[0049] In some implementations, the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and the U-SIG further includes a modulation and coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2. Thus, Bfee can identify that the PPDU is an NDP without calculating the number of symbols in the data field. Thus, Bfee can prepare a procedure for calculating channel state information in advance to obtain a longer processing time, and does not need to calculate that the length of the data part of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps Bfee improve the efficiency of reading the NDP.

[0050] In some implementations, the NDP indication subfield or the PPDU format subfield in the U-SIG indicates that the PPDU is in uncompressed mode. When the PPDU is in uncompressed mode, the subfield indicating the number of EHT-SIG symbols or MU-MIMO users in the U-SIG indicates the number of EHT-SIG symbols. Thus, the subfield indicating the number of EHT-SIG symbols or MU-MIMO users may indicate that the number of EHT-SIG symbols is 1.

[0051] In some implementations, the number of space-time streams subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG indicate the number of space-time streams and the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols may be, for example, the Number of EHT-LTF Symbols, Midamble Periodicity, and Doppler subfields, or may be the Number of EHT-LTF Symbols subfield indicating the number of EHT-LTF symbols separately.

[0052] According to a sixth aspect, the present application further provides a PPDU transmission method, the method comprising: receiving a PPDU, the PPDU being an NDP, the PPDU including an EHT-SIG, the EHT-SIG including an AID subfield indicating an association identifier AID, the AID being used to indicate information about a user of the NDP; and performing channel estimation using NDP.

[0053] Thus, Bfee can determine information about the users of the NDP based on the AID in the EHT-SIG of the NDP, and thus can accurately determine whether the users are those for which Bfee needs to perform channel sounding and feed back beamforming reports.

[0054] The PPDU in this solution is the NDP used in 802.11ax and later standards, which does not contain a data field, and is used by Bfee to perform channel sounding.

[0055] In some implementations, when the user of the NDP is a station, the AID indicated by the AID subfield is the AID of the station. Thus, the station corresponding to the AID can determine based on the AID in the NDP that the station is a station that needs to perform channel sounding and feed back a beamforming report based on the channel sounding result.

[0056] Thus, even if a station fails to read the user field containing the station's AID because the station does not read the NDPA frame correctly, the station can determine based on the NDP that the station is a station that needs to perform channel sounding and feed back a beamforming report based on the channel sounding result, and therefore can improve the success rate of Bfer obtaining the beamforming report. Also, after receiving the NDP, if a device that does not match the AID indicated by the AID subfield reads that the AID indicated by the AID subfield does not match the AID of the device, the device will not continue to receive the NDP, and therefore the power consumption of the device that does not match the AID indicated by the AID subfield can be reduced.

[0057] In some implementations, when the users of the NDP are multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted through broadcast. In this implementation, the EHT-SIG of the NDPA frame transmitted before the NDP includes a multiple stations field, and the AID subfield in the multiple stations field indicates the AID of the station that needs to perform channel sounding and feedback the beamforming report. Thus, the station receives the NDP and determines that the users of the NDP are multiple stations based on the AID subfield of the NDP being 0. Thus, all stations that receive the NDP, or the stations that correspond to the AID indicated by the user field in the NDPA frame, continue to receive the NDP, obtain channel state information based on the NDP, and feedback the beamforming report.

[0058] In some implementations, when the user of the NDP is an access point, the AID indicated by the AID subfield is a default value. The default value can be announced by the AP through broadcast, or can be a fixed value pre-set in a standard, such as 2045. It should be understood that the default value can be another value instead.

[0059] In some implementations, the PPDU further includes a U-SIG, which includes a format subfield and / or a compression subfield, and the format subfield or the compression subfield indicates that the PPDU is an NDP. Thus, after identifying the PPDU, Bfee can identify that the PPDU is an NDP based on the format subfield or the compression subfield. Thus, before the number of symbols in the data field of the PPDU is calculated to be 0, the PPDU can be identified as an NDP, and the PPDU is read based on the format of the NDP, so that Bfee can prepare a procedure for calculating channel state information in advance, obtain a longer processing time, and improve the efficiency of reading the NDP.

[0060] In some implementations, the PPDU further includes a U-SIG and an EHT-LTF, and the U-SIG includes a space-time stream number subfield indicating the number of space-time streams, and the number of EHT-LTFs is greater than the number of space-time streams. Thus, in an aggregated PPDU transmission scenario, when multiple NDPs with the same structure are transmitted on different channels, the number of EHT-LTF symbols of the NDPs transmitted on the channels can be the same even if the spatial streams on the channels are different. This helps align the symbols of the fields of the NDPs to avoid out-of-band interference between different frequency bands.

[0061] According to a seventh aspect, the present application further provides a PPDU transmission device, including a processing unit and a transmitting unit, the processing unit configured to generate a PPDU, the PPDU including a universal signal field U-SIG, the U-SIG including a subfield indicating that the PPDU is a null data packet NDP, and the transmitting unit configured to transmit the PPDU.

[0062] In this way, Bfee receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG indicating that the PPDU is an NDP, and therefore Bfee can prepare the procedure of calculating channel state information in advance to gain more processing time, without having to calculate that the length of the data portion of the PPDU is 0 and then determine that the PPDU is an NDP. The NDP helps Bfee improve the efficiency of receiving the NDP.

[0063] The transmission device can be understood as Bfer. The transmission device can be, for example, an access point or a station. Alternatively, the transmission device is located in an access point or a station.

[0064] In some implementations, the PPDU further includes an Extremely High Throughput-Short Training Field EHT-STF adjacent to and following the U-SIG.

[0065] In some implementations, the subfield indicating that the PPDU is an NDP is an NDP indication subfield, a PPDU format subfield, or a subfield indicating the number of EHT-SIG symbols in the U-SIG.

[0066] In some implementations, the U-SIG further includes a number of spatial streams subfield and / or a subfield indicating the number of very high throughput-long training field EHT-LTF symbols, and the number of spatial streams subfield and / or the subfield indicating the number of EHT-LTF symbols indicates the number of spatial streams and the number of EHT-LTF symbols.

[0067] According to an eighth aspect, the present application further provides a PPDU transmission device, including a processing unit and a transmitting unit. The processing unit is configured to generate a PPDU, the PPDU being an NDP, the PPDU including an ultra-high throughput-signal field EHT-SIG, the number of EHT-SIG symbols being 1, and the EHT-SIG being modulated using BPSK and a code rate of 1 / 2. The transmitting unit is configured to transmit the PPDU. Thus, the number of EHT-SIG symbols can be reduced, and therefore the overhead required for transmitting the NDP can be reduced.

[0068] The transmission device can be understood as Bfer. The transmission device can be, for example, an access point or a station. Alternatively, the transmission device is located in an access point or a station.

[0069] In some implementations, the PPDU further includes a universal signal field U-SIG, which includes a subfield indicating the number of EHT-SIG symbols, which subfield indicates the number of EHT-SIG symbols to be some value greater than or equal to 1.

[0070] In some implementations, the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and the U-SIG further includes a modulation and coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0071] In some implementations, the NDP indication subfield or the PPDU format subfield in the U-SIG indicates that the PPDU is in uncompressed mode.

[0072] In some implementations, the number of space-time streams subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG indicate the number of space-time streams and the number of EHT-LTF symbols.

[0073] According to a ninth aspect, the present application further provides a PPDU transmission device, including a processing unit and a sending unit, the processing unit is configured to generate a PPDU, the PPDU being an NDP, the PPDU including an EHT-SIG, the EHT-SIG including an AID subfield indicating an association identifier AID, the AID being used to indicate information about a user of the NDP, and the sending unit is configured to send the PPDU.

[0074] Thus, Bfee can determine information about the users of the NDP based on the AID in the EHT-SIG of the NDP, and thus can accurately determine whether the users are those for which Bfee needs to perform channel sounding and feed back beamforming reports.

[0075] The transmission device can be understood as Bfer. The transmission device can be, for example, an access point or a station. Alternatively, the transmission device is located in an access point or a station.

[0076] In some implementations, if the user of the NDP is a station, the AID indicated by the AID subfield is the AID of that station.

[0077] In some implementations, if the users of the NDP are multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted via broadcast.

[0078] In some implementations, if the user of the NDP is an access point, the AID indicated by the AID subfield is a default value.

[0079] In some implementations, the PPDU further includes a U-SIG, which includes a format subfield and / or a compression subfield, where the format subfield or the compression subfield indicates that the PPDU is an NDP.

[0080] In some implementations, the PPDU further includes a U-SIG and an EHT-LTF, where the U-SIG includes a number of space-time streams subfield indicating the number of space-time streams, and the number of EHT-LTFs is greater than the number of space-time streams.

[0081] According to a tenth aspect, the present application further provides a PPDU transmission device, including a receiving unit and a processing unit. The receiving unit is configured to receive a PPDU, the PPDU being an NDP, the PPDU including a universal signal field U-SIG, the U-SIG including a subfield indicating that the PPDU is a null data packet NDP. The processing unit is configured to perform channel estimation using the NDP.

[0082] In this way, Bfee receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG indicating that the PPDU is an NDP, and therefore Bfee can prepare the procedure of calculating channel state information in advance to gain more processing time, without having to calculate that the length of the data portion of the PPDU is 0 and then determine that the PPDU is an NDP. The NDP helps Bfee improve the efficiency of receiving the NDP.

[0083] The transmission device may be understood as Bfee. The transmission device may be, for example, a station or an access point. Alternatively, the transmission device is located in an access point or a station.

[0084] In some implementations, the PPDU further includes an Extremely High Throughput-Short Training Field EHT-STF adjacent to and following the U-SIG.

[0085] In some implementations, the subfield indicating that the PPDU is an NDP is an NDP indication subfield, a PPDU format subfield, or a subfield indicating the number of EHT-SIG symbols in the U-SIG.

[0086] In some implementations, the U-SIG further includes a number of spatial streams subfield and / or a subfield indicating the number of very high throughput-long training field EHT-LTF symbols, and the number of spatial streams subfield and / or the subfield indicating the number of EHT-LTF symbols indicates the number of spatial streams and the number of EHT-LTF symbols.

[0087] According to an eleventh aspect, the present application further provides a PPDU transmission device, including a receiving unit and a processing unit. The receiving unit is configured to receive a PPDU, the PPDU being an NDP, the PPDU including an ultra-high throughput-signal field EHT-SIG, the number of EHT-SIG symbols being 1, and the EHT-SIG being modulated using BPSK and a code rate of 1 / 2. The processing unit is configured to perform channel estimation using the NDP. Thus, the number of EHT-SIG symbols can be reduced, and therefore the overhead required for transmitting the NDP can be reduced.

[0088] The transmission device may be understood as Bfee. The transmission device may be, for example, a station or an access point. Alternatively, the transmission device is located in a station or an access point.

[0089] In some implementations, the PPDU further includes a universal signal field U-SIG, which includes a subfield indicating the number of EHT-SIG symbols, which subfield indicates the number of EHT-SIG symbols to be some value greater than or equal to 1.

[0090] In some implementations, the NDP indication subfield or the PPDU format subfield in the U-SIG indicates that the PPDU is in uncompressed mode.

[0091] In some implementations, the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and the U-SIG further includes a modulation and coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0092] In some implementations, the number of space-time streams subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG indicate the number of space-time streams and the number of EHT-LTF symbols.

[0093] According to a twelfth aspect, the present application further provides a PPDU transmission device, including a receiving unit and a processing unit. The receiving unit is configured to receive a PPDU, the PPDU being an NDP, the PPDU including an ultra-high throughput-signal field EHT-SIG, the number of EHT-SIG symbols is 1, and the EHT-SIG is modulated using BPSK and a code rate of 1 / 2. The processing unit is configured to perform channel estimation using the NDP.

[0094] Thus, Bfee can determine information about the users of the NDP based on the AID in the EHT-SIG of the NDP, and thus can accurately determine whether the users are those for which Bfee needs to perform channel sounding and feed back beamforming reports.

[0095] The transmission device may be understood as Bfee. The transmission device may be, for example, a station or an access point. Alternatively, the transmission device is located in a station or an access point.

[0096] In some implementations, if the user of the NDP is a station, the AID indicated by the AID subfield is the AID of that station.

[0097] In some implementations, if the users of the NDP are multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted via broadcast.

[0098] In some implementations, if the user of the NDP is an access point, the AID indicated by the AID subfield is a default value.

[0099] In some implementations, the PPDU further includes a U-SIG, which includes a format subfield and / or a compression subfield, where the format subfield or the compression subfield indicates that the PPDU is an NDP.

[0100] In some implementations, the PPDU further includes a U-SIG and an EHT-LTF, where the U-SIG includes a number of space-time streams subfield indicating the number of space-time streams, and the number of EHT-LTFs is greater than the number of space-time streams.

[0101] For related descriptions of the implementation of the above-mentioned transmission device, please refer to the related content of the implementation of the above-mentioned PPDU transmission method, and the details will not be described again here.

[0102] According to a thirteenth aspect, an implementation of this application further provides a PPDU transmission device. The transmission device includes a processor and a transceiver, and may optionally further include a memory. When the processor executes a computer program or instructions in the memory, a method according to any of the implementations of the first to sixth aspects is performed. The transmission device may be understood as a communication device. The transmission device may be a station or an access point.

[0103] According to a fourteenth aspect, an implementation of this application further provides a computer-readable storage medium having instructions stored thereon for directing a communication device to perform a method according to any of the implementations of the first to sixth aspects.

[0104] According to a fifteenth aspect, an implementation of this application further provides a computer program product, the computer program product including a computer program which, when run on a computer, enables the computer to execute a method according to any of the implementations of the first to sixth aspects.

[0105] According to a sixteenth aspect, the present application further provides a processor configured to execute a method according to any one of the implementations of the first to sixth aspects. In the process of executing these methods, the process of transmitting the above-mentioned information and the process of receiving the above-mentioned information in the above-mentioned methods can be understood as the process of outputting the above-mentioned information by the processor and the process of receiving the above-mentioned input information by the processor. Specifically, when outputting the information, the processor outputs the information to the transceiver, so that the transceiver transmits the information.

[0106] Furthermore, after the information is output by the processor, it may be necessary to perform further processing on the information before it arrives at the transceiver. Similarly, when the processor receives input information, the transceiver receives the information and inputs the information to the processor. Furthermore, after the transceiver receives the information, it may be necessary to perform further processing on the information before it is input to the processor.

[0107] In this case, unless otherwise specified, operations such as transmission, sending, and receiving related to the processor or operations that do not contradict the actual functions or internal logic of the operations in the relevant description, those operations may be understood more generally as operations such as output, receiving, and input of the processor instead of operations such as transmission, sending, and receiving directly performed by the radio frequency circuitry and antenna.

[0108] In one particular implementation, the processor may be a processor specially configured to perform these methods or may be a processor, such as a general-purpose processor, that performs these methods by executing computer instructions in a memory. The memory may be a non-transitory memory, such as a read-only memory (ROM). The memory and the processor may be integrated on the same chip or may be separately located on different chips. The type of memory and the manner in which the memory and the processor are located are not limitations on the implementation of the present invention.

[0109] According to a seventeenth aspect, the present application provides a chip system, comprising a processor and an interface configured to support a communication transmission device in implementing the functions of the method according to any of the first to sixth aspects, such as determining or processing data and / or information in the above-mentioned method. In one possible design, the chip system further comprises a memory, the memory configured to store information and data required for the above-mentioned PPDU transmission device. The chip system may comprise a chip, or may comprise a chip and another discrete device.

[0110] According to an eighteenth aspect, the application provides a functional entity, the functional entity being configured to implement a method according to any of the first to sixth aspects. [Brief description of the drawings]

[0111] [Figure 1] 1 is a schematic diagram of a network architecture of a communication system according to an embodiment of the present application; [Diagram 2] 1 is a schematic diagram of a configuration of a PPDU transmission device according to an embodiment of this application. [Diagram 3] FIG. 1 is a schematic diagram of a chip configuration according to one embodiment of the present application. [Figure 4A] 1 is a schematic diagram of a structure of an HE SU PPDU including a data field. [Figure 4B] 1 is a schematic diagram of a structure of an HE MU PPDU including a data field; [Figure 4C] FIG. 1 is a schematic diagram of the structure of the HE NDP. [Diagram 5] FIG. 2 is a schematic diagram of a structure of an EHT PPDU including a data field according to an embodiment of the present application; [Figure 6] 2 is a schematic flowchart of a PPDU transmission method according to an embodiment of the present application; [Figure 7] 2 is a schematic diagram of an aggregated PPDU transmission scenario according to an embodiment of the present application; [Figure 8] FIG. 2 is a schematic diagram of another aggregated PPDU transmission scenario according to an embodiment of the present application; [Figure 9] FIG. 2 is a schematic diagram of the structure of an NDP according to one embodiment of the present application. [Figure 10] FIG. 13 is a schematic diagram of yet another aggregated PPDU transmission scenario according to an embodiment of the present application; [Figure 11] FIG. 2 is a schematic diagram of the structure of an NDP according to another embodiment of the present application. [Figure 12] 1 is a schematic diagram of a module of a transmission device according to an embodiment of the present application; [Figure 13] 1 is a schematic diagram of a module of a transmission device according to an embodiment of the present application; [Figure 14] 1 is a schematic diagram of a module of a transmission device according to an embodiment of the present application; [Figure 15] 1 is a schematic diagram of a module of a transmission device according to an embodiment of the present application; [Figure 16] 1 is a schematic diagram of a module of a transmission device according to an embodiment of the present application; [Figure 17] 1 is a schematic diagram of a module of a transmission device according to an embodiment of the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0112] The technical solutions in this application are described below with reference to the accompanying drawings.

[0113] For example, FIG. 1 shows a network configuration used in the data transmission method in this application. FIG. 1 is a schematic diagram of a network configuration according to an embodiment of this application. The network configuration may include one or more access point (AP) stations and one or more non-access-point stations (non-AP STAs). For ease of description, in this specification, an access point station is referred to as an access point (AP), and a non-access point station is referred to as a station (STA). The AP is, for example, AP1 and AP2 in FIG. 1, and the STA is, for example, STA1, STA2, and STA3 in FIG. 1.

[0114] An access point can be an access point for a terminal device (e.g., a mobile phone) to access a wired (or wireless) network, and is mainly located in homes, buildings, and parks. A typical coverage radius is tens to hundreds of meters. Certainly, an access point may be located outdoors instead. An access point corresponds to a bridge connecting a wired network and a wireless network. The main function of an access point is to connect various wireless network clients together and to connect a wireless network to an Ethernet. In particular, an access point can be a terminal device (e.g., a mobile phone) or a network device (e.g., a router) equipped with a wireless fidelity (Wi-Fi) chip.

[0115] The access point may be a device supporting the 802.11be standard. Alternatively, the access point may be a device supporting multiple wireless local area network (WLAN) standards of the 802.11 family, such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a. The access point in this application may be a high efficient (HE) AP or an extremely high throughput (EHT) AP, or may be an access point applicable to future Wi-Fi standards.

[0116] An access point may include a processor and a transceiver, the processor configured to control and manage the actions of the access point, and the transceiver configured to receive and transmit information.

[0117] The station may be a wireless communication chip, a wireless sensor, a wireless communication terminal, or the like, and may also be referred to as a user. For example, the station may be a mobile phone supporting a Wi-Fi communication function, a tablet computer supporting a Wi-Fi communication function, a set-top box supporting a Wi-Fi communication function, a smart television supporting a Wi-Fi communication function, an intelligent wearable device supporting a Wi-Fi communication function, an in-vehicle communication device supporting a Wi-Fi communication function, or a computer supporting a Wi-Fi communication function.

[0118] Optionally, the station may support the 802.11be standard. The station may alternatively support multiple wireless local area network (WLAN) standards of the 802.11 family, such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.

[0119] The station may include a processor and a transceiver, the processor configured to control and manage the actions of the access point, and the transceiver configured to receive and transmit information.

[0120] The access point in this application may be a high efficiency (HE) STA or an extremely high throughput (EHT) STA, or may be an STA applicable to future Wi-Fi standards.

[0121] For example, the access points and stations may be devices applied in the Internet of Vehicles, Internet of Things nodes or sensors in the Internet of Things (IoT), smart cameras, smart remote controls, or smart meters / water meters in a smart home, or sensors in a smart city.

[0122] The access point and the station in the embodiment of this application may also be collectively referred to as a PPDU transmission device. The PPDU transmission device may include a hardware structure and a software module, and the above-mentioned functions are implemented in the form of a hardware structure, a software module, or a combination of a hardware structure and a software module. One of the above-mentioned functions may be implemented in the form of a hardware structure, a software module, or a combination of a hardware structure and a software module.

[0123] 2 is a schematic diagram of a configuration of a PPDU transmission device 200 according to an embodiment of this application. As shown in FIG. 2, the transmission device 200 may include a processor 201 and a transceiver 205, and optionally further includes a memory 202.

[0124] The transceiver 205 may be referred to as a transceiver unit, a transceiver machine, a transceiver circuit, or the like, and is configured to implement a transceiver function. The transceiver 205 may include a receiver and a transmitter. The receiver may be referred to as a receiver machine, a receiver circuit, or the like, and is configured to implement a receiving function. The transmitter may be referred to as a transmitter machine, a transmitter circuit, or the like, and is configured to implement a transmitting function.

[0125] The memory 202 can store computer programs, software codes, or instructions 204, which may also be referred to as firmware. The processor 201 can control the MAC layer and the PHY layer by executing the computer programs, software codes, or instructions 203 in the processor 201 or by calling the computer programs, software codes, or instructions 204 stored in the memory 202 to implement the data transmission method provided in the following embodiments of this application.

[0126] The processor 201 may be a central processing unit (CPU), and the memory 202 may be, for example, a read-only memory (ROM) or a random access memory (RAM).

[0127] The processor 201 and transceiver 205 described in this application may be implemented in an integrated circuit (IC), an analog IC, a radio frequency integrated circuit (RFIC), a mixed-signal IC, an application-specific integrated circuit (ASIC), a printed circuit board (PCB), an electronic device, or the like.

[0128] The transmitting device 200 may further include an antenna 206. These modules included in the transmitting device 200 are merely examples for illustration purposes, and are not intended to be limiting in this application.

[0129] As mentioned above, the transmission device 200 described in the above embodiment may be an access point or a station. However, the scope of the transmission device described in this application is not limited thereto, and the configuration of the transmission device may not be limited in FIG. 2. The transmission device may be an independent device or a part of a larger device. For example, the transmission device may be implemented in the following forms: (1) An independent integrated circuit IC, chip, chip system, or subsystem; (2) A set that includes one or more ICs, which may optionally also include a storage component for storing data and instructions; (3) A module that can be incorporated into another device; (4) A receiver, intelligent terminal, wireless device, handheld device, mobile unit, vehicle-mounted device, cloud device, artificial intelligence device, or the like; or (5) Other.

[0130] For the transmission device implemented in the form of a chip or chip system, please refer to the schematic diagram of the configuration of the chip or chip system shown in Figure 3. The chip or chip system shown in Figure 3 includes a processor 301 and an interface 302. There may be more than one processor 301 and there may be more than one interface 302. Optionally, the chip or chip system may include a memory 303.

[0131] The embodiments of this application do not limit the protection scope and applicability of the claims. Those skilled in the art can adaptively change the functions and arrangements of elements in this application, and appropriately omit, replace or add various processes or components without departing from the scope of the embodiments of this application.

[0132] In the related art, a device that transmits an NDPA frame and an NDP can be understood as a beamformer (Bfer), and a device that receives an NDPA frame and an NDP and feeds back a beamforming report based on the NDPA frame and the NDP can be understood as a beamformee (Bfee). Bfer can be an AP or a STA. Bfee can be an STA or an AP.

[0133] In 802.11ax, different PPDUs are separately designed for scenarios in which network equipment performs single user (SU) transmission and multiple user (MU) transmission.

[0134] In 802.11ax, in a scenario where the network device performs single user (SU) transmission, the PPDU transmitted by the network device is the HE SU PPDU. Figure 4A is a schematic diagram of the structure of the HE SU PPDU in 802.11ax. The HE SU PPDU includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal field (L-SIG), a repeating legacy signal field (RL-SIG), a high-efficiency signal field A (HE-SIG A), a high-efficiency short training field (HE-STF), a high-efficiency long training field (HE-LTF), a data field, and a packet extension (PE) field. The L-SIG and the RL-SIG have the same length, and the duration of the field following the L-SIG and indicated by the L-SIG is not an integer multiple of 3.

[0135] In 802.11ax, in a scenario where a network device performs multi-user (MU) transmission, the PPDU transmitted by the network device is the HE MU PPDU. Figure 4B is a schematic diagram of the structure of the HE MU PPDU in 802.11ax. The HE MU PPDU includes an L-STF, an L-LTF, an L-SIG, a RL-SIG, an HE-SIG A, an HE-SIG B, an HE-STF, an HE-LTF, a data field, and a PE field. The L-SIG and the RL-SIG have the same length, and the duration of the field following the L-SIG and indicated by the L-SIG is not an integer multiple of 3.

[0136] In 802.11ax, an HE NDP is designed for the HE PPDU. Figure 4C is a schematic diagram of the structure of the HE NDP in 802.11ax. The HE NDP includes L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG A, HE-STF, HE-LTF, and PE fields.

[0137] PPDUs are classified into NDPs and PPDUs containing a data field. NDPs are PPDUs that do not contain a data field and can be understood as a special PPDU.

[0138] Upon receiving an NDP, Bfee first determines the specific generation of the standard to which the version of the received PPDU belongs based on the L-SIG and RL-SIG, and then calculates that the number of symbols in the data field is 0 and determines that the received PPDU is an NDP.

[0139] Specifically, Bfee detects the L-SIG and RL-SIG, and if these two fields are the same and the duration of the field following the L-SIG and indicated by the L-SIG is not a multiple of 3, Bfee determines that the received signal is an HE PPDU. The L-SIG contains length indication information indicating the sum of the lengths of all fields following the L-SIG in time. The lengths of the HE-SIG-A and HE-STF are fixed. Based on the lengths of the HE-SIG-A and HE-STF, the number of HE-LTFs indicated by the HE-SIG, the length of the guard interval, the size of the HE-LTF, and the packet extension related parameters, Bfee can calculate that the length of the data field is 0 and determine that the received HE PPDU is an HE NDP.

[0140] In the 802.11be standard under discussion, the related art provides a structure of an EHT PPDU including a data field that is compatible with 802.11be. Figure 5 is a schematic diagram of a possible EHT PPDU structure. The EHT PPDU includes an L-STF, an L-LTF, an L-SIG, an RL-SIG, a U-SIG, an EHT-SIG, an EHT-STF, an EHT-LTF, a data field, and a PE field. The L-SIG and the RL-SIG have the same length, and the duration of the field following the L-SIG and indicated by the L-SIG is an integer multiple of 3.

[0141] U-SIG and EHT-SIG are signal fields. U-SIG is used to carry some common information, such as PPDU version indication, uplink / downlink indication, PPDU frequency domain bandwidth indication, and puncture indication. EHT-SIG includes resource allocation indication, data demodulation indication, and the like.

[0142] Table 1 shows the possible structure of the U-SIG in the EHT PPDU including the data field. The U-SIG includes the following subfields: physical layer version identifier indication subfield, uplink / downlink (UL / DL) indication subfield, basic service set color (BSS color) subfield, transmit opportunity (TXOP) subfield, bandwidth and preamble puncture indication subfield, PPDU format subfield, space-time block coding (STBC) subfield, spatial reuse indication subfield, guard interval (GI) and EHT-LTF size subfield, low density parity check extra symbol segment (LDPC extra symbol segment) subfield, pre-FEC padding factor subfield, packet extension disambiguity (PE) subfield, and packet extension puncture indication subfield. disambiguity subfield, number of EHT-SIG symbols or MU-MIMO users subfield, EHT-SIG modulation and coding scheme (MCS) and dual-carrier modulation (DCM) subfield, cyclic redundancy code (CRC), and tail bits. [Table 1]

[0143] The physical layer version indication subfield is used to indicate the generation of the PPDU. The uplink / downlink indication subfield is used to indicate uplink or downlink. The BSS color subfield indicates the color identifier of the BSS in which the Bfer is located. The bandwidth and preamble puncture indication subfield indicates the bandwidth and preamble puncture information of the data packet. The PPDU format subfield is used to indicate the PPDU format. The STBC subfield indicates whether STBC is used for the data part. The low density parity check additional symbol segment subfield indicates whether additional symbol segments are transmitted after LDPC coding is used. The pre-forward error correction padding factor subfield indicates the pre-forward error correction padding factor. The packet extension disambiguity subfield indicates whether the packet extension is ambiguous. The subfield indicating the number of EHT-SIG symbols or MU-MIMO users indicates the number of EHT-SIG symbols or the number of MU-MIMO users. The EHT-SIG MCS·DCM subfield indicates the EHT-SIG MCS and indicates if DCM is used. The CRC is used to verify the information. The tail bits are used to terminate the coding.

[0144] Table 2 shows the possible structure of the EHT-SIG of the EHT PPDU including the data field. The EHT-SIG of the EHT PPDU includes the subfields number of EHT-LTF symbols, midamble periodicity and doppler, preamble puncture indication, cyclic redundancy code (CRC), tail bits, station identity, number of space-time streams (NSTS), coding, modulation and coding scheme (MCS), beam change, beamformed, CRC, and tail bits. The number of bits in each subfield in Table 2 is the number of information bits before coding. [Table 2]

[0145] The EHT-LTF Symbol Number, Midamble Periodicity and Doppler subfields are used to indicate the EHT-LTF symbol number, midamble periodicity and Doppler. The EHT-LTF Symbol Number, Midamble Periodicity and Doppler subfields can be understood as subfields indicating the EHT-LTF symbol number. The Preamble Puncture Indication subfield is used to indicate the preamble puncture mode. The Station Identity subfield is used to indicate an association identifier (AID). The Coding subfield indicates a particular coding mode. The Modulation and Coding Scheme subfield indicates the modulation and coding scheme of the data part. The Beam Changing subfield indicates if beam changing is applied. The Beamformed subfield indicates if beamforming is used.

[0146] It should be understood that the EHT-SIG of the EHT PPDU includes a common field and a user-specific field. The user-specific field includes one or more user fields. The EHT-LTF symbol number, midamble periodicity, and Doppler subfields corresponding to B0-B21, the preamble puncture indication subfield, the cyclic redundancy code, and the tail bits are common fields. The station identity subfield corresponding to B22 and bits after B22, the number of space-time streams subfield, the coding subfield, the modulation and coding scheme subfield, the beam redirection subfield, the beamformed subfield, the CRC, and the tail bits are user-specific fields.

[0147] The Station Identity subfield, Number of Space-Time Streams subfield, Coding subfield, Modulation and Coding Scheme subfield, Beam Modification subfield, and Beamformed subfield are a group of user fields. Usually, two user fields form a group, and every two user fields are followed by a CRC and tail field. If the number of user fields is odd, the last user field forms a group, and the last user field is followed by a CRC and tail field.

[0148] It can be seen that in Table 2, the number of user fields is 1, in which case the number of EHT-SIG symbols is the minimum. When BPSK and a code rate of 1 / 2 are used, the number of EHT-SIG symbols obtained through coding is 2. In this case, in an EHT PPDU including a data field, the number of EHT-SIG symbols can be considered to be 2 or more.

[0149] However, in the 802.11be under discussion, 802.11be only provides the structure of the EHT PPDU including the data field shown in Fig. 5, and does not incorporate the structure of the EHT PPDU without the data field, that is, does not provide the EHT NDP that meets the 802.11be standard. Thus, the AP and STA cannot perform NDP measurement to obtain channel state information.

[0150] Based on the above background, this application provides some NDP structures used in 802.11ax and later standards. Thus, in a scenario where wireless communication is performed using 802.11ax and later standards (e.g., 802.11be), Bfee can perform channel estimation based on NDP and feed back beamforming reports.

[0151] With reference to the PPDU transmission method provided in the embodiment of this application, the structure of the NDP provided in the technical solution of this application will be described below.

[0152] 6 is a schematic flowchart of a PPDU transmission method according to an embodiment of this application. The method may include the following steps:

[0153] 602: Bfer generates a PPDU.

[0154] The PPDU is an NDP used in 802.11ax and later standards and does not contain a data field. The NDP is used by Bfee to perform channel sounding. Channel sounding in this application may also be referred to as channel measurement or channel estimation.

[0155] The NDP may be any of the NDPs provided below in this embodiment of the application and used for 802.11ax and later standards.

[0156] The first type of NDP provided in this embodiment of the present application includes a subfield that indicates that the PPDU is an NDP. Thus, Bfee receiving the NDP can identify the NDP more quickly. This helps improve the efficiency of Bfee reading the NDP.

[0157] The second type of NDP provided in the embodiment of this application includes an EHT-SIG, the number of EHT-SIG symbols is 1, the modulation scheme used in the EHT-SIG is BPSK, and the modulation code rate used in the EHT-SIG is a code rate of 1 / 2. Thus, compared with the EHT-SIG of the PPDU including the data fields shown in Table 2, the number of EHT-SIG symbols is smaller, and therefore the overhead required for transmitting the NDP can be reduced.

[0158] The third type of NDP provided in this embodiment of the present application includes an AID subfield, which is used to indicate information about the user of the NDP. Thus, the Bfee receiving the NDP can determine information about the user of the NDP based on the AID in the EHT-SIG of the NDP, and accurately determine whether the user is one for which the Bfee needs to perform channel sounding and feed back a beamforming report.

[0159] It should be understood that the names of relevant fields (e.g., fields such as EHT-STF, SHT-LTF, and EHT-SIG) in some NDPs provided in this embodiment of the application are determined according to the 802.11be standard after 802.11ax. The names of relevant fields in some NDPs provided in this embodiment of the application may be replaced with names of fields related to the 802.11ax or later standard instead. In this embodiment of the application, the NDP includes multiple subfields. The names of the subfields are not limited in this embodiment of the application. In another embodiment, the names of the subfields may be replaced with other names.

[0160] 604: Bfer transmits a PPDU.

[0161] In response, Bfee receives a PPDU.

[0162] 606: Bfee performs channel estimation using NDP to obtain channel state information.

[0163] Optionally, after the channel state information is obtained, the method may further include step 608, namely, Bfee may send a beamforming report including the channel state information to Bfer.

[0164] Thus, in a scenario in which wireless communication is performed using 802.11ax or later standards (e.g., 802.11be), Bfee can perform channel estimation based on NDP to obtain channel state information and feed back beamforming reports to Bfer.

[0165] In this embodiment of the application, Bfer can be an AP or a STA. Bfee can be a STA or an AP.

[0166] Optionally, before step 602, the method further includes:

[0167] 601: Bfee transmits an NDPA frame, which can include a station information field, which includes an AID subfield used to indicate the AID of a station that needs to perform channel sounding and feed back a beamforming report. Thus, Bfee can determine whether it needs to acquire channel state information based on the AID subfield in the NDPA frame. If yes, Bfee can acquire channel state information within a frequency range corresponding to the partial bandwidth information based on the partial bandwidth information indicated in the NDPA frame by using NDP.

[0168] The following describes in detail the specific structures and corresponding technical effects of some NDPs involved in the above-mentioned method steps and used in the 802.11ax and later standards.

[0169] In some possible implementations, the NDP transmitted in the PPDU transmission method in this embodiment of this application uses the structure of the first type of NDP provided in this embodiment of this application.

[0170] The first type of NDP provided in this embodiment of the application includes a U-SIG, and the U-SIG includes a subfield indicating that the PPDU is an NDP. The Bfee that receives the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG indicating that the PPDU is an NDP, so that the Bfee can prepare a procedure for calculating channel state information in advance to obtain a longer processing time, and does not need to calculate that the length of the data part of the PPDU is 0 and then determine that the PPDU is an NDP. The NDP helps the Bfee to improve the efficiency of receiving the NDP.

[0171] The U-SIG may include at least one of an NDP indication subfield, a PPDU format subfield, or a subfield indicating the number of EHT-SIG symbols. The subfield indicating that the PPDU is an NDP is the NDP indication subfield, the PPDU format subfield, or the subfield indicating the number of EHT-SIG symbols in the U-SIG.

[0172] Specifically, in some embodiments, the U-SIG includes an NDP indication subfield, a PPDU format subfield, or a subfield indicating the number of EHT-SIG symbols, and any one of the NDP indication subfield, the PPDU format subfield, or the subfield indicating the number of EHT-SIG symbols is a subfield indicating that the PPDU is an NDP.

[0173] In some other embodiments, the U-SIG includes an NDP indication subfield and a PPDU format subfield, where either the NDP indication subfield or the PPDU format subfield is a subfield indicating that the PPDU is an NDP; alternatively, the U-SIG includes a PPDU format subfield and a subfield indicating the number of EHT-SIG symbols, where either the PPDU format subfield or the subfield indicating the number of EHT-SIG symbols is a subfield indicating that the PPDU is an NDP; alternatively, the U-SIG includes an NDP indication subfield and a subfield indicating the number of EHT-SIG symbols, where either the NDP indication subfield or the subfield indicating the number of EHT-SIG symbols is a subfield indicating that the PPDU is an NDP.

[0174] In some further alternative embodiments, the U-SIG includes an NDP indication subfield, where the NDP indication subfield is a subfield indicating that the PPDU is an NDP; or the U-SIG includes a PPDU format subfield, where the PPDU format subfield is a subfield indicating that the PPDU is an NDP; or the U-SIG includes a subfield indicating a number of EHT-SIG symbols, where the subfield indicating the number of EHT-SIG symbols is a subfield indicating that the PPDU is an NDP.

[0175] The subfield indicating the number of EHT-SIG symbols may be, but is not limited to, a subfield indicating the number of EHT-SIG symbols or MU-MIMO users, or an EHT-SIG symbol number subfield used only to indicate the number of EHT-SIG symbols.

[0176] The subfield indicating the number of EHT-SIG symbols may indicate, for example, that the number of EHT-SIG symbols is a specified value to indicate that the PPDU is an NDP. For example, the subfield indicating the number of EHT-SIG symbols may indicate, for example, that the number of EHT-SIG symbols is 0 to indicate that the PPDU is an NDP.

[0177] In the related art, Fig. 7 is a schematic diagram of the structure of a PPDU transmitted on a channel in an aggregated PPDU transmission scenario. Four different channels in the frequency domain are respectively used to transmit an HE MU PPDU containing a data field and three EHT PPDUs, each of which contains a data field. The HE MU PPDU containing a data field does not contain a U-SIG or an EHT-SIG, but contains HE-SIG A and HE-SIG B. The positions and numbers of the symbols of HE-SIG A and HE-SIG B in the HE MU PPDU containing a data field are the same as the positions and numbers of the symbols of U-SIG and EHT-SIG. In this way, it can be ensured that the symbols of the PPDUs transmitted on all channels are aligned, so that out-of-band interference between different frequency bands is avoided.

[0178] However, the HE NDP only includes HE-SIG A having two symbols, but does not include HE-SIG B. If the corresponding EHT NDP is designed based on the format of the EHT PPDU including the data field shown in Figure 5, the EHT NDP includes the EHT-SIG. In the aggregated PPDU structure shown in Figure 8, when hybrid transmission is performed on the HE NDP and the EHT NDP designed based on the format of the EHT PPDU including the data field shown in Figure 5, the symbols of the PPDU transmitted on all channels will not be aligned, which will cause out-of-band interference between different frequency bands.

[0179] 9 is a schematic diagram of the structure of an NDP according to an embodiment of this application. In the first type NDP provided in the embodiment of this application, the NDP further includes an EHT-STF adjacent to and following the U-SIG. The EHT-STF immediately follows the U-SIG. The NDP does not include an EHT-SIG. Thus, the EHT NDP uses the structure of the first type NDP in this application. This helps to realize symbol alignment between the EHT NDP and the HE NDP.

[0180] Optionally, the first type NDP in this application may further include an L-STF, an L-LTF, an L-SIG, an RL-SIG, an EHT-STF, an EHT-LTF, and a PE field.

[0181] The L-STF, L-LTF, and L-SIG are used to ensure coexistence between new and legacy equipment. The L-SIG contains a length field that can indicate the number of symbols in each of the fields that follow the L-SIG. The RL-SIG is used to increase the reliability of the legacy signal fields. The EHT-STF is used for automatic gain control for the subsequent fields. The EHT-LTF is used for channel estimation.

[0182] The L-SIG and RL-SIG are the same, and the duration of the field following the L-SIG and indicated by the length field in the L-SIG is an integer multiple of 3. Thus, by detecting the L-SIG and RL-SIG and identifying that the duration of the field following the L-SIG and indicated by the length field in the L-SIG is a multiple of 3, Bfee can identify that the PPDU is an EHT PPDU or a later version PPDU, and can identify the specific version of the PPDU based on the physical layer version indication in the U-SIG.

[0183] Figure 10 is a schematic diagram of an aggregated PPDU transmission scenario. When hybrid transmission is performed on the HE NDP and the EHT NDP using the NDP structure shown in Figure 9 in the aggregated PPDU structure, the symbols of the EHT NDP and the HE NDP can be aligned, so that out-of-band interference occurring between different frequency bands can be avoided.

[0184] As shown in FIG. 9, the first type of NDP in this application does not include an EHT-SIG. The U-SIG does not need to indicate the number of EHT-SIG symbols or MCS, and does not need to indicate coding-related indications, such as an LDPC additional symbol segment indication. A packet extension indication can use a fixed value and therefore does not need to be indicated. Thus, the U-SIG does not need to include a subfield indicating the number of EHT-SIG symbols, an MCS subfield, a low-density parity check additional symbol segment subfield, or a packet extension disambiguity subfield. The bits used to carry these fields in the U-SIG of the PPDU including the data field can be used to carry other information in the U-SIG of the NDP, or the bits used to carry these fields can be used to carry other fields. For example, the bits used to carry these fields can be used to carry a subfield indicating the number of EHT-LTF symbols, allowing the U-SIG of the NDP to include more information.

[0185] It should be understood that in some optional embodiments, based on the structure of the NDP shown in Figure 9, the U-SIG may instead include a subfield indicating the number of EHT-SIG symbols. The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is a specified value, thereby indicating that the PPDU is an NDP.

[0186] Optionally, the U-SIG further includes at least one of a number of spatial streams (NSS) subfield and a subfield indicating the number of EHT-LTF symbols. The NSS subfield and / or the subfield indicating the number of EHT-LTF symbols indicate the NSS and the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols may be, for example, the number of EHT-LTF symbols-midamble-Doppler subfields, or may be the number of EHT-LTF symbols subfield indicating the number of EHT-LTF symbols individually.

[0187] There is a correspondence between NSTS and NSS. When space-time block coding (STBC) is used, NSTS is twice the NSS, and is expressed as NSTS=2*NSS. When STBC is not used, NSTS is the same as NSS, and is expressed as NSTS=NSS. Thus, the NSS subfield indicating NSS may also indicate NSTS. The NSS subfield may be replaced with the NSTS subfield.

[0188] There is a correspondence between the number of EHT-LTF symbols and the NSTS. For example, when the NSTS is 1, the corresponding number of EHT-LTF symbols is 1, when the NSTS is 2, the corresponding number of EHT-LTF symbols is 2, when the NSTS is 3 or 4, the corresponding number of EHT-LTF symbols is 4, when the NSTS is 5 or 6, the corresponding number of EHT-LTF symbols is 6, when the NSTS is 7 or 8, the corresponding number of EHT-LTF symbols is 8, when the NSTS is any number from 9 to 12, the corresponding number of EHT-LTF symbols is 12, and when the NSTS is any number from 13 to 16, the corresponding number of EHT-LTF symbols is 16.

[0189] Specifically, in one embodiment, the U-SIG includes an NSTS subfield and a subfield indicating the number of EHT-LTF symbols. The NSTS subfield indicates the NSTS, and the subfield indicating the number of EHT-LTF symbols indicates the number of EHT-LTF symbols. Alternatively, the U-SIG includes an NSS subfield and a subfield indicating the number of EHT-LTF symbols, and the NSS subfield indicates the NSS and indicates the NSTS based on the above-mentioned correspondence between the NSTS and the NSS. The subfield indicating the number of EHT-LTF symbols indicates the number of EHT-LTF symbols.

[0190] In another embodiment, the U-SIG includes an NSTS subfield, but does not include an NSS subfield or a subfield indicating the number of EHT-LTF symbols. The NSTS subfield indicates NSTS and can indirectly indicate NSS and the number of EHT-LTF symbols based on the above two corresponding relationships. Alternatively, the U-SIG includes an NSS subfield, but does not include an NSTS subfield or a subfield indicating the number of EHT-LTF symbols. The NSS subfield indicates NSS and can indirectly indicate NSTS and the number of EHT-LTF symbols based on the above two corresponding relationships.

[0191] In yet another embodiment, the U-SIG includes a subfield indicating the number of EHT-LTF symbols, but does not include the NSTS or NSS subfield. The subfield indicating the number of EHT-LTF symbols indicates the number of EHT-LTF symbols and indicates at least one of the NSS and the NSTS based on the above correspondence.

[0192] In one embodiment of the option, the contents included in the U-SIG of the first type of NDP in the embodiment of this application are shown in Table 3. Specifically, the U-SIG includes a physical layer version identifier indication subfield, an uplink / downlink (UL / DL) indication subfield, a basic service set color (BSS color) subfield, a transmit opportunity (TXOP) subfield, a bandwidth indication subfield, a PPDU format subfield, an NDP indication subfield, a spatial reuse indication subfield, a guard interval (GI interval)·EHT-LTF size indication subfield, a number of EHT-LTF symbols, midamble periodicity and doppler subfield, a number of spatial streams (NSS) subfield, a CRC, and tail bits. The U-SIG further includes 5 reserved bits that are used to carry other information that needs to be carried. It should be understood that based on the correspondence between NSTS and NSS, the NSS subfield in Table 3 may be replaced with the NSTS subfield. [Table 3]

[0193] The NDP indication subfield indicates that the PPDU is an NDP. For the contents indicated by other subfields in the U-SIG, please refer to the relevant descriptions of the corresponding subfields in Tables 1 and 2. The details will not be described again here.

[0194] It should be understood that the order of the sub-fields and the bits occupied by the sub-fields in Table 3 are not limited in this embodiment of the present application. In another embodiment, adjustments can be made based on the actual situation.

[0195] In some other possible implementations, the NDP transmitted in the PPDU transmission method in this embodiment of this application uses the structure of the second type of NDP provided in this embodiment of this application.

[0196] The second type NDP provided in this embodiment of the application includes an EHT-SIG. The number of EHT-SIG symbols is 1, and the EHT-SIG is modulated using BPSK and a code rate of 1 / 2. Thus, compared with the EHT-SIG of the PPDU including the data portion shown in Table 2, the structure of the second type NDP provided in this embodiment of the application can reduce the number of EHT-SIG symbols, and therefore reduce the overhead required to transmit the NDP.

[0197] Optionally, Figure 11 is a schematic diagram of the structure of an NDP. The second type of NDP provided in this embodiment of this application may further include an L-STF, an L-LTF, an L-SIG, an RL-SIG, an U-SIG, an EHT-STF, an EHT-LTF, and a PE field. The PE field is used to help Bfee obtain a longer processing time. Alternatively, the NDP may not include a PE field. For example, if the processing ability of Bfee is powerful, the NDP may not include a PE field.

[0198] For the description of L-STF, L-LTF, L-SIG, RL-SIG, EHT-STF, and EHT-LTF, and the description of Bfee identifying PPDU, please refer to the related description of the implementation of the structure of the first type of NDP, and the details will not be described again here.

[0199] Based on the structure of the second type of NDP provided in this embodiment of this application, this embodiment of this application provides several indication methods to indicate that a PPDU is an NDP and related techniques used by Bfee to know that a PPDU is an NDP based on the indication.

[0200] In one indication scheme for indicating that a PPDU is an NDP, the U-SIG of the NDP includes a subfield indicating a number of EHT-SIG symbols, where the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is some value greater than or equal to 1. For example, the subfield indicating the number of EHT-SIG symbols may be a subfield indicating the number of EHT-SIG symbols or MU-MIMO users, or may be a number of EHT-SIG symbols subfield.

[0201] Optionally, Bfee may obtain the sum of the lengths of all fields following the L-SIG based on the length indication information in the L-SIG, and obtain the lengths of the RL-SIG, EHT-SIG, EHT-LTF, and PE fields based on the number of EHT-SIG symbols, the number of EHT-LTFs, the length of the guard interval, the size of the EHT-LTF, and the packet extension related parameters indicated in the U-SIG and EHT-SIG. The lengths of the RL-SIG, U-SIG, and EHT-STF are fixed. In this case, Bfee may obtain the length of the data field by subtracting the lengths of the RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF, and PE fields from the sum of the lengths of all fields following the L-SIG obtained based on the length indication information in the L-SIG, and calculate the number of symbols of the data field. If Bfee calculates that the length of the data field is less than or equal to 0, Bfee identifies the PPDU as an NDP.

[0202] It can be understood that the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and Bfee can calculate that the length of the data field in the PPDU is 0 and determine that the PPDU is an NDP. The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is greater than 1, and Bfee can calculate that the length of the data field in the PPDU is less than 0 and determine that the PPDU is an NDP.

[0203] Also, the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and the U-SIG further includes an MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2. As shown in Table 2, in a PPDU including a data field, the number of information bits of the EHT-SIG is 54. When the EHT-SIG is modulated using BPSK and a code rate of 1 / 2, the number of EHT-SIG symbols obtained through coding is more than 1.

[0204] Thus, based on the subfield indicating the number of EHT-SIG symbols indicating that the number of EHT-SIG symbols is 1 and the MCS subfield indicating that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2, Bfee can determine that the PPDU is an NDP. Bfee can identify that the PPDU is an NDP without calculating the number of symbols in the data field. Thus, Bfee can prepare the procedure of calculating channel state information in advance to obtain a longer processing time, and does not need to calculate that the length of the data part of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps Bfee improve the efficiency of reading the NDP.

[0205] In an optional embodiment, the U-SIG further includes an NDP indication subfield and / or a PPDU format subfield. The NDP indication subfield or the PPDU format subfield in the U-SIG indicates that the PPDU is in uncompressed mode. If the PPDU is in uncompressed mode, the subfield indicating the number of EHT-SIG symbols or MU-MIMO users in the U-SIG indicates the number of EHT-SIG symbols. Thus, the subfield indicating the number of EHT-SIG symbols or MU-MIMO users can indicate that the number of EHT-SIG symbols is 1.

[0206] It should be appreciated that in another optional embodiment, if the PPDU is in compressed mode, the EHT-SIG symbol count subfield in the U-SIG indicates that the EHT-SIG symbol count is one.

[0207] In an optional alternative embodiment, the EHT-SIG in the NDP includes common fields but does not include user-specific fields, thus reducing the number of EHT-SIG symbols by omitting the user fields.

[0208] Specifically, as shown in Table 4, the EHT-SIG of the NDP includes a number of EHT-LTF symbols, midamble periodicity and doppler subfield, a preamble puncture indication subfield, a number of space-time streams (NSTS) subfield, a cyclic redundancy code (CRC), and a tail bit. The number of EHT-LTF symbols, midamble periodicity and Doppler subfield may be understood as a subfield indicating the number of EHT-LTF symbols. It should be understood that, based on the correspondence between NSTS and NSS, the NSTS subfield in Table 4 may be replaced with the NSS subfield. [Table 4]

[0209] The EHT-LTF Symbol Number, Midamble Periodicity, and Doppler subfields indicate the EHT-LTF symbol number, midamble periodicity, and Doppler. The Preamble Puncture Indication subfield indicates the preamble puncture mode. The NSTS subfield indicates the number of space-time streams or the number of spatial streams of the STA. Optionally, if space-time block coding is not considered, the NSTS subfield may indicate NSS, or the NSTS subfield in Table 4 may be replaced by the NSS subfield. The CRC is used to verify the information. The tail bits are used to terminate the coding.

[0210] Optionally, the EHT-SIG may include only one of the following subfields: the NSTS subfield, the Number of Spatial Streams (NSS) subfield used to indicate the number of spatial streams, and the Number of EHT-LTF Symbols, Midamble Periodicity, and Doppler subfields. Thus, some fields in the EHT-SIG may be omitted and the bits originally used to carry the omitted fields may be used to carry other information.

[0211] In one possible case, the EHT-SIG contains the EHT-LTF symbol number, midamble periodicity, and Doppler subfields, but does not contain the NSTS or NSS subfields, thus allowing the bits (B12-B15) originally used to carry the NSTS or NSS subfields to carry other information.

[0212] Specifically, the part of the EHT-LTF symbol number, midamble periodicity, and Doppler subfield that originally indicates the EHT-LTF symbol number can be used to indicate the EHT-LTF symbol number, or to indicate NSTS in escape mode. Based on the correspondence between the EHT-LTF symbol number and NSTS and the correspondence between NSS and NSTS in the above related description of the first type of NDP, the EHT-LTF symbol number, midamble periodicity, and Doppler subfield can indicate the EHT-LTF symbol number and NSTS, or the EHT-LTF symbol number and NSS by indicating one of the EHT-LTF symbol number, NSTS, or NSS.

[0213] In another possible case, the EHT-SIG includes an NSTS subfield, but does not include an NSS subfield or an EHT-LTF symbol number, midamble periodicity, or Doppler subfield. Specifically, the NSTS subfield indicates NSTS and indirectly indicates NSS and the EHT-LTF symbol number based on the correspondence between the EHT-LTF symbol number and NSTS and the correspondence between NSS and NSTS in the above related description of the first type of NDP. Thus, the bits (B0-B3) originally used to carry the EHT-LTF symbol number, midamble periodicity, and Doppler subfields may be used to carry other information.

[0214] In yet another possible case, the EHT-SIG includes an NSS subfield, but does not include an NSTS subfield or an EHT-LTF symbol number, midamble periodicity, or Doppler subfield. Specifically, the NSS subfield indicates the NSS and indirectly indicates the NSTS and the EHT-LTF symbol number based on the correspondence between the EHT-LTF symbol number and the NSTS and the correspondence between the NSS and the NSTS in the above related description of the first type of NDP. Thus, the bits (B0-B3) originally used to carry the EHT-LTF symbol number, midamble periodicity, and Doppler subfields may be used to carry other information.

[0215] It should be understood that in the second type NDP provided in the embodiment of this application, the above two optional embodiments may be implemented separately or in combination.

[0216] It can be seen that in the second type NDP provided in the embodiment of this application, there is only one EHT-SIG symbol, thus reducing the overhead of the NDP while still carrying sufficient information.

[0217] In some further possible implementations, the NDP transmitted in the PPDU transmission method in this embodiment of this application uses the structure of the third type of NDP provided in this embodiment of this application.

[0218] The third type of NDP provided in this embodiment of the application includes an EHT-SIG. The EHT-SIG includes a user field. The user field includes an AID subfield indicating an AID. Specifically, the EHT-SIG of the NDP includes a common field and a user-specific field. The common field indicates some common information, for example, preamble indication information indicating the puncturing status of the EHT NDP. The user-specific field includes a user field.

[0219] In one possible implementation, the AID is used to indicate information about the NDP user. The NDP user can be one or more STAs or can be an AP. Thus, Bfee can determine information about the NDP user based on the AID in the NDP EHT-SIG. Thus, Bfee can accurately determine whether the user is one for which Bfee needs to perform channel sounding and feed back beamforming reports.

[0220] Below, some embodiments are provided in which the AID subfield indicates information about the user of the NDP.

[0221] In some embodiments, if the user of the NDP is one station, the AID indicated by the AID subfield is the AID of the station. It can be understood that in this embodiment, only one station receives the NDP, then performs channel estimation, and feeds back a beamforming report.

[0222] Thus, the station corresponding to the AID can determine based on the AID in the NDP that the station is a station that needs to perform channel sounding and feed back a beamforming report based on the channel sounding result. Thus, even if the station fails to read the user field containing the station's AID because the station does not read the NDPA frame correctly, the station can determine based on the NDP that the station is a station that needs to perform channel sounding and feed back a beamforming report based on the channel sounding result, thus improving the success rate of Bfer obtaining the beamforming report. Also, after receiving the NDP, if a device that does not match the AID indicated by the AID subfield reads that the AID indicated by the AID subfield does not match the AID of the device, the device will not continue to receive the NDP, thus reducing the power consumption of the device that does not match the AID indicated by the AID subfield.

[0223] In some other embodiments, when the users of the NDP are multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted through broadcast. In this embodiment, the EHT-SIG of the NDPA frame transmitted before the NDP includes a multiple stations field, and the AID subfield in the multiple stations field indicates the AID of the station that needs to perform channel sounding and feed back the beamforming report. Thus, the station receives the NDP and determines that the users of the NDP are multiple stations based on the AID subfield of the NDP being 0.

[0224] Thus, all stations that receive the NDP, or stations that correspond to the AID indicated by the user field in the NDPA frame, continue to receive the NDP, obtain channel state information based on the NDP, and feed back beamforming reports.

[0225] In some further alternative embodiments, if the user of the NDP is an access point, the AID indicated by the AID subfield is a default value. The default value can be announced by the AP through broadcast, or can be a fixed value pre-set in a standard, such as 2045. It should be understood that the default value can alternatively be another value.

[0226] Optionally, for the structure of the third type NDP provided in this embodiment of this application, please refer to Figure 11. The NDP further includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-STF, EHT-LTF, and PE fields. For the functions of these subfields, please refer to the related description of the first type NDP provided in the above embodiment of this application. The details will not be described again here.

[0227] It can be seen that the structure of the NDP is similar to the format of the EHT PPDU including the data field shown in Figure 5. Thus, for Bfee to receive the NDP, Bfee can receive the NDP by using the same receiving policy as the EHT PPDU including the data field.

[0228] For the manner in which Bfee identifies the version of the PPDU, please refer to the relevant description of Bfee identifying the version of the PPDU in the above embodiment corresponding to the first type of NDP provided in the embodiment of this application, and the details will not be described again here.

[0229] As for how Bfee identifies that the PPDU is an NDP, using the way Bfee calculates the length of the data field in the above-mentioned embodiment corresponding to the second type of NDP provided in the embodiment of this application, it can calculate that the length of the data field is 0, and as a result, Bfee identifies the PPDU as an NDP.

[0230] In the third type of NDP provided in the embodiment of this application, some simpler indication schemes can be used instead to indicate that a PPDU is an NDP, thus allowing Bfee to determine that a PPDU is an NDP in a simpler and earlier way, prepare in advance the procedure of calculating channel state information, and obtain longer processing time.

[0231] In one indication manner for indicating that a PPDU is an NDP, the U-SIG includes a format subfield and / or a compression subfield, and the format subfield or the compression subfield in the U-SIG indicates that the PPDU is an NDP. Thus, after identifying the PPDU, Bfee can identify that the PPDU is an NDP based on the format subfield or the compression subfield. Thus, the PPDU can be identified as an NDP before the number of symbols in the data field of the PPDU is calculated to be 0, and the PPDU is read based on the format of the NDP, so that Bfee can prepare a procedure for calculating channel state information in advance, obtain a longer processing time, and improve the efficiency of reading the NDP.

[0232] This indication scheme for indicating that a PPDU is an NDP may be implemented in combination with any embodiment in which the AID subfield indicates information about the user of the NDP, or may be implemented separately.

[0233] Specifically, in one embodiment, the U-SIG includes a format subfield and a compressed subfield, where the format subfield or the compressed subfield indicates that the PPDU is an NDP. In another embodiment, the U-SIG includes a format subfield, where the format subfield indicates that the PPDU is an NDP. In yet another embodiment, the U-SIG includes a compressed subfield, where the compressed subfield indicates that the PPDU is an NDP.

[0234] Indeed, in another embodiment, the format subfield or the compression subfield may instead indicate that the PPDU is a PPDU in compressed mode. In this embodiment, the PPDU is an NDP in compressed mode, which can reduce the overhead of the EHT-SIG for the NDP.

[0235] In another indication manner of indicating that a PPDU is an NDP, an AID in an EHT-SIG indicates that the PPDU is an NDP. Specifically, to indicate that a PPDU is an NDP, an AID in an EHT-SIG is a default value indicating that the PPDU is an NDP. The value indicating that the PPDU is an NDP may be, for example, 2044. Certainly, in another embodiment, the value indicating that the PPDU is an NDP may be another value instead.

[0236] In an optional embodiment, the number of EHT-LTFs is greater than the number of space-time streams. Thus, in an aggregated PPDU transmission scenario, when multiple NDPs whose structure is the same as that of the third type NDP are transmitted on different channels, the number of EHT-LTF symbols of the NDPs transmitted on those channels can be the same, even if the spatial streams on those channels are different. This helps align the symbols of the fields of the NDPs to avoid out-of-band interference between different frequency bands.

[0237] In the above-mentioned embodiments provided in this application, the method provided in the embodiment of this application is described separately from the perspective of an access point and from the perspective of a station. In order to implement the functions of the above-mentioned methods provided in the embodiment of this application, the access point and the station may include a hardware structure and a software module, and implement the above-mentioned functions in the form of a hardware structure, a software module, or a combination of a hardware structure and a software module. One of the above-mentioned functions may be implemented in the form of a hardware structure, a software module, or a combination of a hardware structure and a software module.

[0238] 12 is a schematic diagram of modules of a transmission device 1200 according to an embodiment of this application. The transmission device 1200 includes a processing unit 1201 and a sending unit 1202.

[0239] The processing unit 1201 is configured to generate a PPDU, where the PPDU includes a universal signal field U-SIG, where the U-SIG includes a subfield indicating that the PPDU is a null data packet NDP.

[0240] The sending unit 1202 is configured to send the PPDU.

[0241] In this way, Bfee receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG indicating that the PPDU is an NDP, and therefore Bfee can prepare the procedure of calculating channel state information in advance to gain more processing time, without having to calculate that the length of the data portion of the PPDU is 0 and then determine that the PPDU is an NDP. The NDP helps Bfee improve the efficiency of receiving the NDP.

[0242] The transmission device 1200 can be understood as a Bfer. The transmission device 1200 can be, for example, an access point or a station. Alternatively, the transmission device 1200 is disposed in an access point or a station. The processing unit 1201 of the transmission device 1200 can be a processor, and the transmission unit 1202 of the transmission device 1200 can be a transceiver.

[0243] In some embodiments, the PPDU further includes an Very High Throughput-Short Training Field EHT-STF adjacent to and following the U-SIG.

[0244] In some embodiments, the subfield indicating that the PPDU is an NDP is an NDP indication subfield, a PPDU format subfield, or a subfield indicating the number of EHT-SIG symbols in the U-SIG.

[0245] In some embodiments, the U-SIG further includes a number of spatial streams subfield and / or a subfield indicating the number of very high throughput-long training field EHT-LTF symbols, and the number of spatial streams subfield and / or the subfield indicating the number of EHT-LTF symbols indicates the number of spatial streams and the number of EHT-LTF symbols.

[0246] 13 is a schematic diagram of a module of a transmission device according to an embodiment of this application. The transmission device 1300 includes a processing unit 1301 and a sending unit 1302.

[0247] The processing unit 1301 is configured to generate a PPDU, where the PPDU is an NDP, where the PPDU includes an ultra-high throughput-signal field EHT-SIG, where the number of EHT-SIG symbols is 1, and where the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0248] The sending unit 1302 is configured to send the PPDU.

[0249] Thus, the number of EHT-SIG symbols can be reduced, and therefore the overhead required to transmit the NDP.

[0250] The transmission device 1300 can be understood as a Bfer. The transmission device 1300 can be, for example, an access point or a station. Alternatively, the transmission device is disposed in an access point or a station. The processing unit 1301 of the transmission device 1300 can be a processor, and the transmission unit 1302 of the transmission device 1300 can be a transceiver.

[0251] In some embodiments, the PPDU further includes a universal signal field U-SIG, which includes a subfield indicating a number of EHT-SIG symbols, the subfield indicating the number of EHT-SIG symbols indicating that the number of EHT-SIG symbols is some value greater than or equal to 1.

[0252] In some embodiments, the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and the U-SIG further includes a modulation and coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0253] In some embodiments, the NDP indication subfield or the PPDU format subfield in the U-SIG indicates that the PPDU is in uncompressed mode.

[0254] In some embodiments, the number of space-time streams subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG indicate the number of space-time streams and the number of EHT-LTF symbols.

[0255] 14 is a schematic diagram of a module of a transmission device according to an embodiment of this application. The transmission device 1400 includes a processing unit 1401 and a sending unit 1402.

[0256] The processing unit 1401 is configured to generate a PPDU, where the PPDU is an NDP, and the PPDU includes an EHT-SIG, where the EHT-SIG includes an AID subfield indicating an association identifier AID, where the AID is used to indicate information about a user of the NDP.

[0257] The transmitting unit 1402 is configured to transmit the PPDU.

[0258] Thus, Bfee can determine information about the users of the NDP based on the AID in the EHT-SIG of the NDP, and thus can accurately determine whether the users are those for which Bfee needs to perform channel sounding and feed back beamforming reports.

[0259] The transmission device 1400 can be understood as a Bfer. The transmission device 1400 can be, for example, an access point or a station. Alternatively, the transmission device is disposed in an access point or a station. The processing unit 1401 of the transmission device 1400 can be a processor, and the transmission unit 1402 of the transmission device 1400 can be a transceiver.

[0260] In some embodiments, if the user of the NDP is a station, the AID indicated by the AID subfield is the AID of that station.

[0261] In some embodiments, if the users of the NDP are multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted via broadcast.

[0262] In some embodiments, if the user of the NDP is an access point, the AID indicated by the AID subfield is a default value.

[0263] In some embodiments, the PPDU further includes a U-SIG, the U-SIG including a format subfield and / or a compression subfield, where the format subfield or the compression subfield indicates that the PPDU is an NDP.

[0264] In some embodiments, the PPDU further includes a U-SIG and an EHT-LTF, where the U-SIG includes a number of space-time streams subfield indicating a number of space-time streams, where the number of EHT-LTFs is greater than the number of space-time streams.

[0265] 15 is a schematic diagram of a module of a transmission device according to an embodiment of this application. The transmission device 1500 includes a receiving unit 1501 and a processing unit 1502.

[0266] The receiving unit 1501 is configured to receive a PPDU, where the PPDU is an NDP, and the PPDU includes a universal signal field U-SIG, where the U-SIG includes a subfield indicating that the PPDU is a null data packet NDP.

[0267] The processing unit 1502 is configured to perform channel estimation using the NDP.

[0268] Bfee receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG indicating that the PPDU is an NDP, so Bfee can prepare the procedure of calculating channel state information in advance to obtain a longer processing time, and does not need to calculate that the length of the data portion of the PPDU is 0 and then determine that the PPDU is an NDP. The NDP helps Bfee improve the efficiency of receiving the NDP.

[0269] The transmission device 1500 may be understood as Bfee. The transmission device 1500 may be, for example, a station or an access point. Alternatively, the transmission device 1500 is disposed in a station or an access point. The processing unit 1502 of the transmission device 1500 may be a processor, and the receiving unit 1501 of the transmission device 1500 may be a transceiver.

[0270] In some embodiments, the PPDU further includes an Very High Throughput-Short Training Field EHT-STF adjacent to and following the U-SIG.

[0271] In some embodiments, the subfield indicating that the PPDU is an NDP is an NDP indication subfield, a PPDU format subfield, or a subfield indicating the number of EHT-SIG symbols in the U-SIG.

[0272] In some embodiments, the U-SIG further includes a number of spatial streams subfield and / or a subfield indicating the number of very high throughput-long training field EHT-LTF symbols, and the number of spatial streams subfield and / or the subfield indicating the number of EHT-LTF symbols indicates the number of spatial streams and the number of EHT-LTF symbols.

[0273] 16 is a schematic diagram of a module of a transmission device according to an embodiment of this application. The transmission device 1600 includes a receiving unit 1601 and a processing unit 1602.

[0274] The receiving unit 1601 is configured to receive a PPDU, where the PPDU is an NDP, the PPDU includes an ultra-high throughput-signal field EHT-SIG, the number of EHT-SIG symbols is 1, and the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0275] The processing unit 1602 is configured to perform channel estimation using the NDP.

[0276] Thus, the number of EHT-SIG symbols can be reduced, and therefore the overhead required to transmit the NDP.

[0277] The transmission device 1600 can be understood as Bfee. The transmission device 1600 can be, for example, a station or an access point. Alternatively, the transmission device 1600 is disposed in a station or an access point. The processing unit 1602 of the transmission device 1600 can be a processor, and the receiving unit 1601 of the transmission device 1600 can be a transceiver.

[0278] In some embodiments, the PPDU further includes a universal signal field U-SIG, which includes a subfield indicating the number of EHT-SIG symbols, the subfield indicating the number of EHT-SIG symbols indicating that the number of EHT-SIG symbols is some value greater than or equal to 1.

[0279] In some embodiments, the NDP indication subfield or the PPDU format subfield in the U-SIG indicates that the PPDU is in uncompressed mode.

[0280] In some embodiments, the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is 1, and the U-SIG further includes a modulation and coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0281] In some embodiments, the number of space-time streams subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG indicate the number of space-time streams and the number of EHT-LTF symbols.

[0282] 17 is a schematic diagram of a module of a transmission device according to an embodiment of this application. The transmission device 1700 includes a receiving unit 1701 and a processing unit 1702.

[0283] The receiving unit 1701 is configured to receive a PPDU, where the PPDU is an NDP, the PPDU includes an ultra-high throughput-signal field EHT-SIG, the number of EHT-SIG symbols is 1, and the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0284] The processing unit 1702 is configured to perform channel estimation using the NDP.

[0285] Thus, Bfee can determine information about the users of the NDP based on the AID in the EHT-SIG of the NDP, and thus can accurately determine whether the users are those for which Bfee needs to perform channel sounding and feed back beamforming reports.

[0286] The transmitting device 1600 can be understood as Bfee. The transmitting device 1700 can be, for example, a station or an access point. Alternatively, the transmitting device 1700 is disposed in a station or an access point. The processing unit 1702 of the transmitting device 1700 can be a processor, and the receiving unit 1701 of the transmitting device 1700 can be a transceiver.

[0287] In some embodiments, if the user of the NDP is a station, the AID indicated by the AID subfield is the AID of that station.

[0288] In some embodiments, if the users of the NDP are multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted via broadcast.

[0289] In some embodiments, if the user of the NDP is an access point, the AID indicated by the AID subfield is a default value.

[0290] In some embodiments, the PPDU further includes a U-SIG, the U-SIG including a format subfield and / or a compression subfield, where the format subfield or the compression subfield indicates that the PPDU is an NDP.

[0291] In some embodiments, the PPDU further includes a U-SIG and an EHT-LTF, where the U-SIG includes a number of space-time streams subfield indicating a number of space-time streams, where the number of EHT-LTFs is greater than the number of space-time streams.

[0292] For the relevant content of the above-mentioned transmission device embodiment, please refer to the relevant content of the above-mentioned method embodiment, and the details will not be described again here.

[0293] The application further provides a computer readable storage medium having a computer program stored thereon, which, when executed by a computer, implements the functionality of any of the method embodiments described above.

[0294] This application further provides a computer program product, which when executed by a computer, implements the functionality of any of the method embodiments described above.

[0295] It should be further understood that the terms "first," "second," "third," "fourth," and various numbers used in this specification are used merely for purposes of distinction for ease of description and are not to be construed as limitations on the scope of this specification.

[0296] It should be understood that the term "and / or" in this specification only describes an association relationship for describing related objects, and represents that three relationships may exist. For example, A and / or B may represent three cases: only A exists, both A and B exist, and only B exists. Also, the character " / " in this specification generally indicates an "or" relationship between related objects.

[0297] It should be understood that in the embodiment of this application, the sequence numbers of the above processes do not mean any execution sequence. The execution sequence of the processes should be determined based on the functions and internal logic of the processes, and should not constitute any limitation on the implementation process of the embodiment of this application.

[0298] Those skilled in the art can recognize that, in combination with the examples described in the embodiments disclosed in this specification, the units and algorithm steps can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether a function is performed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to realize the described functions for each specific application, and the implementation should not be considered to go beyond the scope of this application.

[0299] It can be clearly understood by those skilled in the art that, for the purpose of simple and concise description, the detailed working processes of the above-mentioned systems, devices and units can be referred to the corresponding processes in the above-mentioned method embodiments, and the details will not be described again here.

[0300] In some embodiments provided in this application, it should be understood that the disclosed system, device, and method may be implemented in other ways. For example, the described device embodiment is merely an example. For example, the unit division is merely a logical function division, and may be other divisions in actual implementation. For example, multiple units or components may be combined or integrated into other systems, or some features may be ignored or not implemented. In addition, the shown or described mutual couplings or direct couplings or communication connections may be implemented via some interface. Indirect couplings or communication connections between multiple devices or units may be implemented in electrical, mechanical, or other forms.

[0301] The units described as separate parts may or may not be physically separated, and the parts shown as units may or may not be physical units, located in one location or distributed over multiple network units. Some or all of the units may be selected according to actual requirements to achieve the objectives of the solutions in the embodiments.

[0302] Additionally, multiple functional units in the embodiments of this application may be integrated into a single processing unit, or each of those units may exist physically alone, or two or more units may be integrated into a single unit.

[0303] When functions are implemented in the form of a software functional unit and sold or used as an independent product, the functions may be stored in a computer-readable storage medium. Based on this understanding, the technical solution in this application may be essentially implemented in the form of a software product, or a part of the technical solution may be contributed to the existing technology. The computer software product is stored in a storage medium and includes some instructions to instruct a computer device (which may be a personal computer, a server, or a network device, or the like) to execute all or part of the steps of the method in the embodiments of this application. The above-mentioned storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0304] The sequence of steps of the methods in the embodiments of this application can be adjusted, combined and deleted based on actual requirements.

[0305] The modules in the apparatus in the embodiments of this application can be combined, divided and deleted based on actual requirements.

[0306] Finally, the above embodiments are merely intended to describe the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the above embodiments, those skilled in the art should understand that, without departing from the scope of the technical solutions of the embodiments of this application, those skilled in the art can still make modifications to the technical solutions described in the above embodiments, or make equivalent substitutions for some technical features thereof.

Claims

1. An access point, a processing unit used to generate a physical layer protocol data unit (PPDU), the PPDU being a null data packet (NDP), the PPDU including an very high throughput signal (EHT-SIG) field and a universal signal (U-SIG) field, the U-SIG field including a subfield indicating that the number of symbols in the EHT-SIG field is 1, the EHT-SIG field being modulated using binary phase shift keying (BPSK) and a code rate of 1 / 2; a transmission unit used for transmitting the PPDU; having The subfield indicating that the number of symbols in the EHT-SIG field is 1 and the subfield indicating that the EHT-SIG field is modulated using the BPSK and the 1 / 2 code rate are used to indicate that the PPDU is an NDP. Access point.

2. 2. The access point of claim 1, wherein the U-SIG field further includes a modulation and coding scheme (MCS) subfield, the MCS subfield indicating that the EHT-SIG field is modulated using the BPSK and the code rate of 1 / 2.

3. The access point of claim 1 , wherein an NDP indication subfield or a PPDU format subfield in the U-SIG field indicates that the PPDU is in an uncompressed mode.

4. The access point of any one of claims 1 to 3, wherein the PPDU further includes an Very High Throughput Long Training (EHT-LTF) field, the EHT-SIG field further including a subfield indicating a number of spatial streams and a subfield indicating a number of symbols of the EHT-LTF field.

5. A physical layer protocol data unit (PPDU) transmission method, comprising: generating a physical layer protocol data unit (PPDU), the PPDU being a null data packet (NDP), the PPDU including an very high throughput signal (EHT-SIG) field and a universal signal (U-SIG) field, the U-SIG field including a subfield indicating that the number of symbols of the EHT-SIG field is 1, the EHT-SIG field being modulated using binary phase shift keying (BPSK) and a code rate of 1 / 2; transmitting the PPDU; and having The subfield indicating that the number of symbols in the EHT-SIG field is 1 and the subfield indicating that the EHT-SIG field is modulated using the BPSK and the 1 / 2 code rate are used to indicate that the PPDU is an NDP. method.

6. 6. The method of claim 5, wherein the U-SIG field further includes a modulation and coding scheme (MCS) subfield, the MCS subfield indicating that the EHT-SIG field is modulated using the BPSK and the code rate of 1 / 2.

7. The method of claim 5, wherein an NDP indication subfield or a PPDU format subfield in the U-SIG field indicates that the PPDU is in a non-compressed mode.

8. The method according to any one of claims 5 to 7, wherein the PPDU further includes an Very High Throughput Long Training (EHT-LTF) field, the EHT-SIG field further including a subfield indicating a number of spatial streams and a subfield indicating a number of symbols of the EHT-LTF field.

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