PPDU transmission method and related apparatus

Abstract

This application provides a PPDU transmission method and related apparatus. [Solution] The method involves generating a PPDU, which includes a universal signaling field U-SIG, where the U-SIG includes a subfield indicating that the PPDU is a null data packet (NDP), and transmitting the PPDU. Thus, a Bfee receiving the NDP can identify the NDP more quickly. This helps improve the efficiency of the Bfee reading the NDP. The PPDU is an NDP used in 802.11ax and later standards. In scenarios where wireless communication is performed using 802.11ax and later standards (e.g., 802.11be), the Bfee can perform channel estimation based on the NDP.

Description

Technical Field

[0001] This application claims priority to Chinese Patent Application No. 202010506948.X, titled "PPDU Transmission Method and Related Device", filed with the China National Intellectual Property Administration on June 5, 2020, and incorporates the entire application herein by reference. This application relates to the field of wireless local area network technology, and in particular, to a PPDU transmission method and related devices.

Background Art

[0002] In a wireless system such as a wireless local area network (WLAN), for example, in order to implement functions such as beamforming (BF), rate control, and resource allocation, an access point (AP) and a station (STA) need to obtain channel state information in advance. In WLAN, the procedure for obtaining channel state information is called channel sounding. In the related art, in the process of the AP executing channel sounding, first, in order for the AP to notify the STA that needs to execute channel sounding, the AP transmits a null data packet announcement (NDPA) frame. Then, after a short interframe space (SIFS), the AP transmits a null data packet (NDP) without a data field. The STA executes channel estimation using the NDP, and then feeds back channel state information (CSI) using a beamforming report (BF report) frame. Then, the AP transmits a physical layer protocol data unit (PPDU) based on the channel state information fed back by the STA.

[0003] In the 802.11ax standard, PPDU is referred to as high-efficiency (HE) PPDU, while in the 802.11be standard, PPDU is referred to as extremely high-throughput (EHT) PPDU.

[0004] However, in the related technologies, only the structure of HE NDP for HE PPDU is provided, and the structure of EHT NDP has not been designed. [Overview of the Initiative]

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

[0006] According to a first aspect, the application provides a PPDU transmission method, which includes generating a physical layer protocol data unit (PPDU), the PPDU comprising a universal signaling field (U-SIG), the U-SIG comprising a subfield indicating that the PPDU is a null data packet (NDP), and transmitting the PPDU.

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

[0008] An instrument that transmits an NDP can be understood as a beamformer (Bfer). An instrument that receives an NDP and performs channel estimation based on the NDP can be understood as a beamformee (Bfee). A Bfer can be an AP or an STA. A Bfee can 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 an NDP receiving device 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 obtain a longer processing time by pre-preparing the procedure for calculating channel state information, and does not need to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps to improve the efficiency of NDP reception.

[0010] Optionally, the subfield indicating that the PPDU is an NDP is the NDP indication subfield, the PPDU format subfield, or the EHT-SIG symbol count subfield within 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 follows immediately after the U-SIG. The NDP does not include the EHT-SIG. Thus, the NDP structure 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 over the EHT NDP and the HE NDP in an aggregated PPDU transmission scenario, thereby avoiding out-of-band interference between different frequency bands.

[0012] NDP does not include EHT-SIG. U-SIG does not need to indicate the EHT-SIG symbol count or modulation and coding scheme (MCS), nor does it need to indicate coding-related indicators such as low-density parity check (LDPC) or additional symbol segment indications. Packet extension indications can use fixed values ​​and therefore do not need to be indicated.

[0013] Thus, the U-SIG does not need to include subfields indicating the EHT-SIG symbol count, the MCS subfield, the LDPC additional symbol segment subfield, or the packet extension disambiguity subfield. Bits used to carry these fields in the U-SIG of a PPDU containing data fields can be used to carry other information in the U-SIG of an NDP, or vice versa. For example, by using the bits used to carry these fields to carry a subfield indicating the EHT-LTF symbol count, the NDP U-SIG can contain more information.

[0014] It should be understood that, in some optional implementations, based on the NDP structure 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 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 the number of EHT-SIG symbols or MU-MIMO users, or an EHT-SIG symbol count subfield used to indicate only the number of EHT-SIG symbols.

[0015] Optionally, U-SIG further includes a subfield indicating the number of spatial streams and / or the number of ultra-high throughput-long training (EHT-LTF) symbols, where the subfields indicate the number of spatial streams and / or the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols can be, for example, the EHT-LTF symbol count-mid-amble periodicity-Doppler subfield, or it can be the EHT-LTF symbol count subfield indicating the number of EHT-LTF symbols individually.

[0016] According to a second aspect, one implementation of this application further provides a PPDU transmission method, which is: The process includes generating a PPDU, which is an NDP, which includes an ultra-high throughput signal field EHT-SIG, which has 1 EHT-SIG symbol, and which is modulated using BPSK and half the code rate, and transmitting the PPDU.

[0017] This PPDU is an NDP used in standards 802.11ax and later, 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 can 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 indicates that the number of EHT-SIG symbols is one or more. 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 count 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 the Bfee receiving the NDP can determine that the PPDU is an NDP by calculating that the length of the data field in the PPDU is 0. The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is greater than 1, and the Bfee can determine that the PPDU is an NDP by calculating that the length of the data field in the PPDU is less than 0.

[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 / coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and half the code rate.

[0022] Thus, Bfee can identify that a PPDU is an NDP without calculating the number of symbols in the data field. In this way, Bfee can gain longer processing time by pre-preparing the procedure for calculating channel state information, without having to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. This helps improve the efficiency of Bfee in reading NDPs.

[0023] In some implementations, the NDP indication subfield or PPDU format subfield within 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 within 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.

[0024] In some implementations, the spatiotemporal stream number subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG represent the spatiotemporal stream number and the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols can be, for example, the EHT-LTF symbol number, mid-amble periodicity, and Doppler subfield, or it can be the EHT-LTF symbol number subfield that individually indicates the number of EHT-LTF symbols.

[0025] According to a third aspect, the application further provides a PPDU transmission method, the method comprising 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 the user of the NDP, and transmitting the PPDU.

[0026] Thus, Bfee can determine information about the NDP users based on the AIDs within the NDP's EHT-SIG. Thus, Bfee can accurately determine whether it is a user for which the Bfee needs to perform channel sounding and feedback a beamforming report.

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

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

[0029] Thus, even if the station fails to correctly read the NDPA frame and misses reading the user field including the station's AID, the station can determine, based on the NDP, that the station needs to perform channel sounding and feedback a beamforming report based on the channel sounding result. Therefore, the success rate of Bfer obtaining the beamforming report can be improved.

[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 its AID, the device will not continue to receive the NDP. Therefore, the power consumption of devices that do not match the AID indicated by the AID subfield can be reduced.

[0031] In some implementations, if the NDP user is multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted via broadcast. In this implementation, the EHT-SIG of the NDPA frame transmitted before the NDP includes multiple station fields, and the AID subfield within these station fields indicates the AID of the station that needs to perform channel sounding and provide feedback on beamforming reports. Thus, a station receives the NDP and, based on the AID subfield of the NDP being 0, determines that the NDP user is multiple stations. Thus, all stations receiving the NDP, or the station corresponding to the AID indicated by the user field in the NDPA frame, continue to receive the NDP, obtain channel status information based on the NDP, and provide feedback on beamforming reports.

[0032] In some implementations, when the NDP user is an access point, the AID indicated by the AID subfield is a default value. This default value can be announced by the AP via broadcast, or it can be a fixed value pre-configured in the standard, such as 2045. It should be understood that the default value may be a different value.

[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, by identifying the PPDU as an NDP before calculating that the number of symbols in the PPDU's data fields is zero, and reading the PPDU based on the NDP format, Bfee can pre-prepare the procedure for calculating channel state information, gain a longer processing time, and improve NDP read efficiency.

[0034] In some implementations, the PPDU further includes a U-SIG and an EHT-LTF, where the U-SIG includes a spatiotemporal stream count subfield indicating the number of spatiotemporal streams, and the EHT-LTF count is greater than the spatiotemporal stream count. Thus, in an aggregated PPDU transmission scenario, when multiple NDPs of the same structure 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 to align the symbols of the NDP fields and avoid out-of-band interference between different frequency bands.

[0035] According to a fourth aspect, the application further provides a PPDU transmission method, which includes receiving a PPDU, the PPDU being an NDP, the PPDU including a universal signaling 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 an NDP used in standards 802.11ax and later, 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 an NDP receiving device 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 obtain a longer processing time by pre-preparing the procedure for calculating channel state information, and does not need to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps to improve the efficiency of NDP reception.

[0038] Optionally, the subfield indicating that the PPDU is an NDP is the NDP indication subfield, the PPDU format subfield, or the EHT-SIG symbol count subfield within 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 follows immediately after the U-SIG. The NDP does not include the EHT-SIG. Thus, the NDP structure 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 over the EHT NDP and the HE NDP in an aggregated PPDU transmission scenario, thereby avoiding out-of-band interference between different frequency bands.

[0040] NDP does not include EHT-SIG. U-SIG does not need to indicate the EHT-SIG symbol count or MCS, nor does it need to indicate coding-related indicators such as LDPC additional symbol segment indications. Packet extension indications can use fixed values ​​and therefore do not need to be indicated.

[0041] Thus, the U-SIG does not need to include subfields indicating the EHT-SIG symbol count, the MCS subfield, the LDPC additional symbol segment subfield, or the packet extension disambiguity subfield. Bits used to carry these fields in the U-SIG of a PPDU containing data fields can be used to carry other information in the U-SIG of an NDP, or vice versa. For example, by using the bits used to carry these fields to carry a subfield indicating the EHT-LTF symbol count, the NDP U-SIG can contain more information.

[0042] It should be understood that, in some optional implementations, based on the NDP structure 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 in order 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 the number of EHT-SIG symbols or MU-MIMO users, or an EHT-SIG symbol count subfield used to indicate only the number of EHT-SIG symbols.

[0043] Optionally, U-SIG further includes a subfield indicating the number of spatial streams and / or the number of ultra-high throughput-long training (EHT-LTF) symbols, where the subfields indicate the number of spatial streams and / or the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols can be, for example, the EHT-LTF symbol count-mid-amble periodicity-Doppler subfield, or it can be the EHT-LTF symbol count 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 comprising receiving a PPDU, the PPDU being an NDP, the PPDU including an ultra-high throughput signal field EHT-SIG, the EHT-SIG having 1 symbol, and the EHT-SIG being modulated using BPSK and a 1 / 2 code rate, and performing channel estimation using the NDP.

[0045] This PPDU is an NDP used in standards 802.11ax and later, 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 can 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, the subfield indicating the number of EHT-SIG symbols being one or more. 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 count subfield used solely 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 the Bfee receiving the NDP can determine that the PPDU is an NDP by calculating that the length of the data field in the PPDU is 0. The subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is greater than 1, and the Bfee can determine that the PPDU is an NDP by calculating that the length of the data field in the PPDU is less than 0.

[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 / coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and half the code rate. Thus, Bfee can identify that the PPDU is an NDP without calculating the number of symbols in the data field. Thus, Bfee can gain a longer processing time by pre-preparing the procedure for calculating channel state information, without having to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. This helps improve the efficiency of Bfee in reading NDPs.

[0050] In some implementations, the NDP indication subfield or PPDU format subfield within 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 within 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.

[0051] In some implementations, the spatiotemporal stream number subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG represent the spatiotemporal stream number and the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols can be, for example, the EHT-LTF symbol number, mid-amble periodicity, and Doppler subfield, or it can be the EHT-LTF symbol number subfield that individually indicates the number of EHT-LTF symbols.

[0052] According to the sixth aspect, this application further provides a PPDU transmission method, which is: Receiving 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 the NDP user, and receiving a PPDU, where 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 the NDP user, This includes performing channel estimation using NDP.

[0053] Thus, Bfee can determine information about the NDP user based on the AID in the NDP's EHT-SIG. Thus, Bfee can accurately determine whether that Bfee is a user that needs to perform channel sounding and provide feedback on beamforming reports.

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

[0055] In some implementations, if the NDP user is a single station, the AID indicated by the AID subfield is the AID of that station. Thus, the station corresponding to the AID can determine, based on the AID in the NDP, that it is a station that needs to perform channel sounding and provide feedback of a beamforming report based on the channel sounding results.

[0056] Thus, even if a station fails to correctly read the NDPA frame and consequently fails to read the user field containing the station's AID, the station can determine, based on the NDP, that it is a station that needs to perform channel sounding and provide feedback on beamforming reports based on the channel sounding results, thereby improving the success rate of Bfer obtaining beamforming reports. Furthermore, if a device that does not match the AID indicated by the AID subfield after receiving the NDP reads that the AID indicated by the AID subfield does not match the AID of that device, the device will not continue to receive NDPs, thus reducing the power consumption of the device whose AID does not match the AID indicated by the AID subfield.

[0057] In some implementations, if the NDP user is multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted via broadcast. In this implementation, the EHT-SIG of the NDPA frame transmitted before the NDP includes multiple station fields, and the AID subfield within these station fields indicates the AID of the station that needs to perform channel sounding and provide feedback on beamforming reports. Thus, a station receives the NDP and, based on the AID subfield of the NDP being 0, determines that the NDP user is multiple stations. Thus, all stations receiving the NDP, or the station corresponding to the AID indicated by the user field in the NDPA frame, continue to receive the NDP, obtain channel status information based on the NDP, and provide feedback on beamforming reports.

[0058] In some implementations, when the NDP user is an access point, the AID indicated by the AID subfield is a default value. This default value can be announced by the AP via broadcast, or it can be a fixed value pre-configured in the standard, such as 2045. It should be understood that the default value may be a different value.

[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, by identifying the PPDU as an NDP before calculating that the number of symbols in the PPDU's data fields is 0, and by reading the PPDU based on the NDP format, Bfee can pre-prepare the procedure for calculating channel state information, gain a longer processing time, and improve NDP read efficiency.

[0060] In some implementations, the PPDU further includes a U-SIG and an EHT-LTF, where the U-SIG includes a spatiotemporal stream count subfield indicating the number of spatiotemporal streams, and the EHT-LTF count is greater than the spatiotemporal stream count. Thus, in an aggregated PPDU transmission scenario, when multiple NDPs of the same structure 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 to align the symbols of the NDP fields and avoid out-of-band interference between different frequency bands.

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

[0062] Thus, the Bfee receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG that indicates the PPDU is an NDP. Therefore, the Bfee can prepare the procedure for calculating channel state information in advance, thus gaining more processing time, and does not need to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps improve the efficiency of the Bfee in receiving NDPs.

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

[0064] In some implementations, the PPDU further includes an ultra-high throughput-short training field (EHT-STF) adjacent to and following the U-SIG.

[0065] In some implementations, the subfield indicating that a PPDU is an NDP is either the NDP indication subfield, the PPDU format subfield, or the EHT-SIG symbol count subfield within the U-SIG.

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

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

[0068] The transmission device may be understood as a Bfer. The transmission device may be, for example, an access point or a station. Alternatively, the transmission device may be located at an access point or 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, and the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is one or more.

[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 / coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and half the code rate.

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

[0072] In some implementations, the spatiotemporal stream count subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG represent the spatiotemporal stream count and the number of EHT-LTF symbols.

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

[0074] Thus, Bfee can determine information about the NDP user based on the AID in the NDP's EHT-SIG. Thus, Bfee can accurately determine whether that Bfee is a user that needs to perform channel sounding and provide feedback on beamforming reports.

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

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

[0077] In some implementations, if the NDP user is 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 NDP user 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, the format subfield or the compression subfield indicating that the PPDU is an NDP.

[0080] In some implementations, the PPDU further includes a U-SIG and an EHT-LTF, the U-SIG including a spatiotemporal stream count subfield indicating the number of spatiotemporal streams, and the EHT-LTF count is greater than the spatiotemporal stream count.

[0081] According to a tenth aspect, the application further provides a PPDU transmission device including a receiving unit and a processing unit. The receiving unit is configured to receive a PPDU, which is an NDP, which includes a universal signaling field U-SIG, which includes 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] Thus, the Bfee receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG that indicates the PPDU is an NDP. Therefore, the Bfee can prepare the procedure for calculating channel state information in advance, thus gaining more processing time, and does not need to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps improve the efficiency of the Bfee in receiving NDPs.

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

[0084] In some implementations, the PPDU further includes an ultra-high throughput-short training field (EHT-STF) adjacent to and following the U-SIG.

[0085] In some implementations, the subfield indicating that a PPDU is an NDP is either the NDP indication subfield, the PPDU format subfield, or the EHT-SIG symbol count subfield within the U-SIG.

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

[0087] According to the eleventh aspect, the application further provides a PPDU transmission device including a receiving unit and a processing unit. The receiving unit is configured to receive a PPDU, which is an NDP, which includes an ultra-high throughput signaling field EHT-SIG, which has 1 EHT-SIG symbol, and which is modulated using BPSK and a 1 / 2 code rate. 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 to transmit the NDP can be reduced.

[0088] The transmission device may be understood as a Bfee. The transmission device may be, for example, a station or an access point. Alternatively, the transmission device may be located at a station or 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, and the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is one or more.

[0090] In some implementations, the NDP indication subfield or PPDU format subfield within 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 / coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and half the code rate.

[0092] In some implementations, the spatiotemporal stream count subfield and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG represent the spatiotemporal stream count and the number of EHT-LTF symbols.

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

[0094] Thus, Bfee can determine information about the NDP user based on the AID in the NDP's EHT-SIG. Thus, Bfee can accurately determine whether that Bfee is a user that needs to perform channel sounding and provide feedback on beamforming reports.

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

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

[0097] In some implementations, if the NDP user is 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 NDP user 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, the format subfield or the compression subfield indicating that the PPDU is an NDP.

[0100] In some implementations, the PPDU further includes a U-SIG and an EHT-LTF, the U-SIG including a spatiotemporal stream count subfield indicating the number of spatiotemporal streams, and the EHT-LTF count is greater than the spatiotemporal stream count.

[0101] For further details regarding the implementation of the transmission device described above, please refer to the related content on the implementation of the PPDU transmission method described above. Details will not be explained again here.

[0102] According to the 13th aspect, one implementation of this application further provides a PPDU transmission device. The transmission device includes a processor and a transceiver, and may optionally further include memory. When the processor executes a computer program or instruction in the memory, a method according to any implementation 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 the fourteenth aspect, one implementation of the present application further provides a computer-readable storage medium which stores instructions which instruct a communication device to perform a method according to any of the implementations of the first to sixth aspects.

[0104] According to the 15th aspect, one implementation of the present application further provides a computer program product, which includes a computer program, which, when run on a computer, enables the computer to perform a method according to any of the implementations of the first to sixth aspects.

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

[0106] Furthermore, after the processor outputs information, it may be necessary to perform further processing on the information before it reaches the transceiver. Similarly, when the processor receives input information, the transceiver receives the information and inputs it 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, or unless such operations are inconsistent with the actual function or internal logic of the operations described in the relevant section, the operations related to the processor, such as transmission, transmission, and reception, may be understood more generally as the operations of the processor, such as output, reception, and input, rather than directly as operations such as transmission, transmission, and reception performed by radio frequency circuits and antennas.

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

[0109] According to the 17th aspect, the application provides a chip system. The chip system includes a processor and interfaces configured to support a communication transmission device in implementing a function in a manner according to any aspect of the first to sixth aspects, for example, determining or processing at least one of data and information in the manner described above. In one possible design, the chip system further includes a memory configured to store the information and data necessary for the PPDU transmission device described above. The chip system may include a chip, or it may include a chip and another discrete device.

[0110] According to the 18th aspect, the application provides a functional entity, which is configured to implement a method according to any aspect of the 1st to 6th aspects. [Brief explanation of the drawing]

[0111] [Figure 1] This is a schematic diagram of the network architecture of a communication system according to one embodiment of this application. [Figure 2] This is a schematic diagram of the configuration of a PPDU transmission device according to one embodiment of this application. [Figure 3] This is a schematic diagram of the configuration of a chip according to one embodiment of this application. [Figure 4A] This is a schematic diagram of the structure of HE SU PPDU, including the data fields. [Figure 4B] This is a schematic diagram of the structure of HE MU PPDU, including the data fields. [Figure 4C] This is a schematic diagram of the HE NDP structure. [Figure 5] This is a schematic diagram of the structure of an EHT PPDU including a data field, according to one embodiment of this application. [Figure 6] This is a schematic flowchart of a PPDU transmission method according to one embodiment of this application. [Figure 7] This is a schematic diagram of an aggregated PPDU transmission scenario according to one embodiment of this application. [Figure 8] This is a schematic diagram of another aggregated PPDU transmission scenario according to one embodiment of this application. [Figure 9] This is a schematic diagram of the structure of an NDP according to one embodiment of this application. [Figure 10] This is a schematic diagram of yet another aggregated PPDU transmission scenario according to one embodiment of this application. [Figure 11] This is a schematic diagram of the structure of an NDP according to another embodiment of this application. [Figure 12] This is a schematic diagram of a transmission device module according to one embodiment of this application. [Figure 13] This is a schematic diagram of a transmission device module according to one embodiment of this application. [Figure 14] This is a schematic diagram of a transmission device module according to one embodiment of this application. [Figure 15] This is a schematic diagram of a transmission device module according to one embodiment of this application. [Figure 16] This is a schematic diagram of a transmission device module according to one embodiment of this application. [Figure 17] This is a schematic diagram of a transmission device module according to one embodiment of this application. [Modes for carrying out the invention]

[0112] The technical solutions in this application will be described below with reference to the attached drawings.

[0113] For example, Figure 1 shows the configuration of a network used in a data transmission method in this application. Figure 1 is a schematic diagram of a network configuration according to one 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 explanation, in this specification, access point stations are referred to as access points (APs) and non-access-point stations are referred to as stations (STAs). APs are, for example, AP1 and AP2 in Figure 1, and STAs are, for example, STA1, STA2, and STA3 in Figure 1.

[0114] An access point can be a point of access for terminal devices (e.g., mobile phones) 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, access points may also be located outdoors. An access point acts as a bridge connecting wired and wireless networks. The main function of an access point is to connect various wireless network clients together and to connect wireless networks to Ethernet. Specifically, an access point can be a terminal device (e.g., a mobile phone) or network device (e.g., a router) equipped with a Wireless Fidelity (Wi-Fi) chip.

[0115] The access point may be a device that supports the 802.11be standard. Alternatively, the access point may be a device that supports 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-efficiency (HE) AP or an extremely high-throughput (EHT) AP, or an access point that is compatible with future Wi-Fi standards.

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

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

[0118] Optionally, the station may support the 802.11be standard. Alternatively, the station may support multiple wireless local area network (WLAN) standards in 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 is configured to control and manage the actions of the access point, and the transceiver is 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 an STA applicable to future Wi-Fi standards.

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

[0122] The access points and stations in the embodiments of this application may also be collectively referred to as PPDU transmission devices. A PPDU transmission device may include a hardware structure and software modules, and the functions described above are implemented in the form of a hardware structure, a software module, or a combination of a hardware structure and software modules. One of the functions described above may be implemented in the form of a hardware structure, a software module, or a combination of a hardware structure and software modules.

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

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

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

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

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

[0128] The transmission device 200 may further include an antenna 206. These modules included in the transmission device 200 are merely illustrative examples and are not limited to this application.

[0129] As described above, the transmission device 200 described in the above embodiments 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 to that shown in Figure 2. The transmission device may be a standalone device or part of a relatively 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 comprising 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 other devices; (4) a receiver, intelligent terminal, wireless device, handheld device, mobile unit, in-vehicle device, cloud device, artificial intelligence device, or similar; or (5) anything else.

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

[0131] The embodiments of this application do not limit the scope and applicability of the claims. Those skilled in the art can adaptively modify the function and arrangement of the elements in this application, or omit, replace, or add various processes or components as appropriate, without departing from the scope of the embodiments of this application.

[0132] In related technologies, equipment that transmits NDPA frames and NDPs may be understood as a beamformer (Bfer), and equipment that receives NDPA frames and NDPs and feeds back beamforming reports based on NDPA frames and NDPs may be understood as a beamformee (Bfee). A Bfer may be an AP or an STA. A Bfee may be an STA or an AP.

[0133] In 802.11ax, different PPDUs are designed separately for scenarios where network devices perform single-user (SU) transmission and multiple-user (MU) transmission.

[0134] In 802.11ax, in a scenario where network equipment performs single-user (SU) transmission, the PPDU transmitted by the network equipment is an HE SU PPDU. Figure 4A is a schematic diagram of the structure of an HE SU PPDU in 802.11ax. An 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 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 scenarios where network devices perform multiple-user (MU) transmission, the PPDU transmitted by the network device is an HE MU PPDU. Figure 4B is a schematic diagram of the structure of an HE MU PPDU in 802.11ax. An HE MU PPDU includes L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG A, HE-SIG B, HE-STF, HE-LTF, a data field, and a PE field. The L-SIG and 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] 802.11ax describes the design of the HE NDP for HE PPDU. Figure 4C is a schematic diagram of the HE NDP structure 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 that include data fields. NDPs are PPDUs that do not include data fields and can be understood as a special type of PPDU.

[0138] Upon receiving an NDP, Bfee first determines the specific generation of the standard to which the received PPDU version belongs based on the L-SIG and RL-SIG, and then calculates that the number of symbols in the data field is 0 to determine 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 that shows the sum of the lengths of all fields following the L-SIG in time. The lengths of HE-SIG-A and HE-STF are fixed. Based on the lengths of HE-SIG-A and HE-STF, the number of HE-LTF indicated by the HE-SIG, the length of the guard interval, the size of the HE-LTF, and packet extension-related parameters, Bfee can calculate that the data field length is 0 and determine that the received HE PPDU is an HE NDP.

[0140] In the 802.11be standard currently under discussion, related technologies provide a structure for EHT PPDUs that includes data fields, compliant with 802.11be. Figure 5 is a schematic diagram of a possible EHT PPDU structure. The EHT PPDU includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-SIG, EHT-STF, EHT-LTF, data fields, and PE fields. The L-SIG and RL-SIG have the same length, and the duration of the fields 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 information indicating the PPDU version, uplink / downlink information, frequency domain bandwidth information of the PPDU, and puncture indication information. EHT-SIG includes information indicating resource allocation, data demodulation information, and similar information.

[0142] Table 1 shows the possible structures of the U-SIG of the EHT PPDU, including the data field. U-SIG includes subfields for: Physical Layer Version Identifier (Version Identifier), Uplink / Downlink (UL / DL), Basic Service Set Color (BSS Color), Transmit Opportunity (TXOP), Bandwidth / Preamble Puncture (Preamble Puncture), PPDU Format (PPDU Format), Space-Time Block Coding (STBC), Spatial Reuse (Spatial Reuse), Guard Interval (GI) / EHT-LTF Size (EHT-LTF Size), Low Density Parity Check Extra Symbol Segment (LDPC), Pre-FEC Padding Factor (Pre-FEC), and Packet Extension Disambiguity (PE). It includes a disambiguity subfield, a number of EHT-SIG symbols or MU-MIMO users subfield, an EHT-SIG modulation and coding scheme (MCS) or dual-carrier modulation (DCM) subfield, a cyclic redundancy code (CRC), and a tail bit. [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 to which the Bfer is located. The Bandwidth / 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 an STBC is used for the data portion. The Low-Density Parity Check Additional Symbol Segment subfield indicates whether an additional symbol segment is 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 packet extensions are ambiguous. The EHT-SIG Symbol or MU-MIMO User Count subfield indicates the number of EHT-SIG symbols or MU-MIMO users. The EHT-SIG MCS·DCM subfield indicates the use of EHT-SIG MCS and whether DCM is used. The CRC is used to verify the information. The tail bit is used to terminate the coding.

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

[0145] The EHT-LTF symbol count, mid-amble periodicity, and Doppler subfield are used to indicate the EHT-LTF symbol count, mid-amble periodicity, and Doppler. The EHT-LTF symbol count, mid-amble periodicity, and Doppler subfield can be understood as a subfield indicating the EHT-LTF symbol count. The preamble puncture indication subfield is used to indicate the preamble puncture mode. The station identification information subfield is used to indicate the association identifier (AID). The coding subfield indicates a specific coding mode. The modulation / coding scheme subfield indicates the modulation / coding scheme of the data portion. The beam change subfield indicates whether beam change is applied. The beamformed subfield indicates whether beamforming is used.

[0146] It should be understood that the EHT-SIG of the EHT PPDU includes common fields and user-specific fields. User-specific fields include one or more user fields. The common fields are the EHT-LTF symbol count, mid-amble periodicity, Doppler subfield, preamble puncture indication subfield, cyclic redundancy code, and tail bit, corresponding to B0-B21. The user-specific fields are the station identification information subfield, spatiotemporal stream count subfield, coding subfield, modulation / coding scheme subfield, beam change subfield, beamformed subfield, CRC, and tail bit, corresponding to B22 and the bits after B22.

[0147] The station identification information subfield, spatiotemporal stream count subfield, coding subfield, modulation / coding scheme subfield, beam change subfield, and beamformed subfield are groups of user fields. Typically, two user fields form a group, followed by a CRC and tail field for every two user fields. If the number of user fields is odd, the last user field forms a group, followed by a CRC and tail field.

[0148] In Table 2, the number of user fields is 1, and in this case, the number of EHT-SIG symbols is minimal. When BPSK and a 1 / 2 coding rate are used, the number of EHT-SIG symbols obtained through coding is 2. In this case, it can be assumed that the number of EHT-SIG symbols in an EHT PPDU containing data fields is 2 or more.

[0149] However, the 802.11be standard currently under discussion only provides the structure of an EHT PPDU that includes the data field shown in Figure 5, and does not incorporate the structure of an EHT PPDU that does not include the data field. In other words, it does not provide an EHT NDP that satisfies the 802.11be standard. Thus, APs and STAs cannot perform NDP measurements to obtain channel status information.

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

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

[0152] Figure 6 is a schematic flowchart of a PPDU transmission method according to one 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 standards 802.11ax and later, 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 in this embodiment of this application and used in standards 802.11ax and later, as described below.

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

[0157] The second type of NDP provided in the embodiments of this application includes an EHT-SIG, has one EHT-SIG symbol, uses a BPSK modulation scheme for the EHT-SIG, and uses a 1 / 2 code rate for the EHT-SIG. Thus, compared to the EHT-SIG of a PPDU containing the data fields shown in Table 2, the number of EHT-SIG symbols is reduced, and therefore the overhead required to transmit the NDP can be reduced.

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

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

[0160] 604: Bfer sends PPDU.

[0161] In response, Bfee receives the PPDU.

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

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

[0164] Thus, in scenarios where wireless communication is performed using standards later than 802.11ax (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 this application, Bfer may be AP or STA. Bfee may be STA or AP.

[0166] Optionally, before step 602, the method may further include the following:

[0167] 601: Bfee transmits an NDPA frame which may include a station information field, which may include an AID subfield used to indicate the AID of the station that needs to perform channel sounding and provide feedback on beamforming reports. Thus, Bfee can determine, based on the AID subfield in the NDPA frame, whether it needs to obtain channel state information. If yes, Bfee can use NDP to obtain channel state information within the frequency range corresponding to the partial bandwidth information indicated in the NDPA frame.

[0168] The following describes in detail the specific structures and corresponding technical effects of several NDPs that are involved in the steps of the method described above and are used in standards from 802.11ax onwards.

[0169] In some possible implementations, the NDP transmitted by 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 this application includes a U-SIG, the U-SIG including a subfield indicating that the PPDU is an NDP. A 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 the Bfee can gain a longer processing time by pre-preparing a procedure for calculating channel state information, without having to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps to improve the efficiency of the Bfee in receiving the NDP.

[0171] A U-SIG may include at least one of the following subfields: an NDP indication subfield, a PPDU format subfield, or a subfield indicating the number of EHT-SIG symbols. A subfield indicating that a PPDU is an NDP is one of the subfields in the U-SIG that indicates the NDP indication subfield, a PPDU format subfield, or an EHT-SIG symbol count subfield.

[0172] Specifically, in some embodiments, the U-SIG includes an NDP indication subfield, a PPDU format subfield, or a subfield indicating the EHT-SIG symbol count. One of the NDP indication subfield, the PPDU format subfield, or the EHT-SIG symbol count subfield is the 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, wherein either the NDP indication subfield or the PPDU format subfield is a subfield indicating that the PPDU is an NDP; or the U-SIG includes a PPDU format subfield and a subfield indicating the number of EHT-SIG symbols, wherein 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; or the U-SIG includes an NDP indication subfield and a subfield indicating the number of EHT-SIG symbols, wherein 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 other embodiments, the U-SIG includes an NDP indication subfield, the NDP indication subfield being a subfield indicating that the PPDU is an NDP; or the U-SIG includes a PPDU format subfield, the PPDU format subfield being a subfield indicating that the PPDU is an NDP; or the U-SIG includes a subfield indicating the EHT-SIG symbol count, the EHT-SIG symbol count subfield being 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 count subfield used solely to indicate the number of EHT-SIG symbols.

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

[0177] In the related technology, Figure 7 is a schematic diagram of the structure of PPDUs transmitted on a channel in an aggregated PPDU transmission scenario. Four different channels in the frequency domain are 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 contains HE-SIG A and HE-SIG B, but does not contain U-SIG or EHT-SIG. The position and number of symbols for HE-SIG A and HE-SIG B within the HE MU PPDU containing a data field are the same as the position and number of symbols for U-SIG and EHT-SIG. Thus, it is possible to ensure that the symbols of PPDUs transmitted on all channels are aligned, and as a result, out-of-band interference between different frequency bands is avoided.

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

[0179] Figure 9 is a schematic diagram of the structure of an NDP according to one embodiment of this application. In the first type of 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 follows immediately after the U-SIG. The NDP does not include an EHT-SIG. Thus, the EHT NDP uses the structure of the first type of NDP in this application. This helps to achieve symbol alignment between the EHT NDP and the HE NDP.

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

[0181] L-STF, L-LTF, and L-SIG are used to ensure the coexistence of new and conventional equipment. L-SIG includes a length-indicating field and can indicate the number of symbols within each of the fields following the L-SIG. RL-SIG is used to improve the reliability of legacy signal fields. EHT-STF is used for automatic gain control of subsequent fields. 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, indicated by the length field within the L-SIG, is an integer multiple of 3. Thus, Bfee can detect the L-SIG and RL-SIG, identify that the duration of the field following the L-SIG, indicated by the length field within the L-SIG, is a multiple of 3, identify that the PPDU is an EHT PPDU or a later version of the PPDU, and then 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. In an aggregated PPDU structure, when hybrid transmission is performed over an HE NDP and an EHT NDP using the NDP structure shown in Figure 9, the symbols of the EHT NDP and HE NDP can be aligned, and as a result, out-of-band interference occurring between different frequency bands can be avoided.

[0184] As shown in Figure 9, the first type of NDP in this application does not include an EHT-SIG. The U-SIG does not need to indicate the EHT-SIG symbol count or MCS, nor does it need to indicate coding-related indicators, such as LDPC additional symbol segment indications. Packet extension indications can use fixed values ​​and therefore do not need to be indicated. Thus, the U-SIG does not need to include subfields indicating the EHT-SIG symbol count, MCS subfields, low-density parity check additional symbol segment subfields, or packet extension disambiguity subfields. Bits used to carry these fields in the U-SIG of a PPDU containing data fields can be used to carry other information in the U-SIG of the NDP, or bits used to carry these fields can be used to carry other fields. For example, by using bits used to carry these fields to carry a subfield indicating the EHT-LTF symbol count, the U-SIG of the NDP can contain more information.

[0185] It should be understood that, in some optional embodiments, based on the NDP structure 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 PPDU is an NDP by indicating that the number of EHT-SIG symbols is a specified value.

[0186] Optionally, the U-SIG further includes at least one of the following subfields: 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 represent the NSS and the number of EHT-LTF symbols. The subfield indicating the number of EHT-LTF symbols can be, for example, an EHT-LTF symbol count-mid-amble-Doppler subfield, or an EHT-LTF symbol count subfield that shows the number of EHT-LTF symbols individually.

[0187] A correspondence exists between NSTS and NSS. When space-time block coding (STBC) is used, NSTS is twice that of 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, an NSS subfield that represents NSS can also represent NSTS. An NSS subfield can be replaced by an NSTS subfield.

[0188] A correspondence exists between the number of EHT-LTF symbols and NSTS. For example, if NSTS is 1, the corresponding number of EHT-LTF symbols is 1; if NSTS is 2, the corresponding number of EHT-LTF symbols is 2; if NSTS is 3 or 4, the corresponding number of EHT-LTF symbols is 4; if NSTS is 5 or 6, the corresponding number of EHT-LTF symbols is 6; if NSTS is 7 or 8, the corresponding number of EHT-LTF symbols is 8; if NSTS is any number from 9 to 12, the corresponding number of EHT-LTF symbols is 12; and if 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 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, where the NSS subfield indicates NSS and also indicates NSTS based on the aforementioned correspondence between NSTS and 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 two correspondences described above. 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 two correspondences described above.

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

[0192] In one optional embodiment, Table 3 shows the contents included in the U-SIG of the first type of NDP in this embodiment. Specifically, the U-SIG includes a physical layer version identifier indicator subfield, an uplink / downlink (UL / DL) indicator subfield, a basic service set color (BSS color) subfield, a transmit opportunity (TXOP) subfield, a bandwidth indicator subfield, a PPDU format subfield, an NDP indicator subfield, a spatial reuse indicator subfield, a guard interval (GI interval) / EHT-LTF size indicator subfield, a number of EHT-LTF symbols, midamble periodicity and doppler subfield, a number of spatial streams (NSS) subfield, a CRC, and a tail bit. The U-SIG further includes 5 bits as reserved bits 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 subfields in Table 3 may be replaced with NSTS subfields. [Table 3]

[0193] The NDP indication subfield indicates that the PPDU is an NDP. For information on the content indicated by other subfields within the U-SIG, please refer to the corresponding subfield descriptions in Tables 1 and 2. Further details will not be provided here.

[0194] It should be understood that the order of the subfields in Table 3 and the bits occupied by the subfields are not limited to this embodiment of this application. In other embodiments, adjustments may be made based on the actual circumstances.

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

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

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

[0198] For explanations of L-STF, L-LTF, L-SIG, RL-SIG, EHT-STF, and EHT-LTF, and for an explanation of how Bfee identifies PPDUs, please refer to the relevant explanation of the implementation of the structure of the first type of NDP. Further details will not be explained here.

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

[0200] In one indication scheme for indicating that a PPDU is an NDP, the NDP's U-SIG includes a subfield indicating the number of EHT-SIG symbols, which indicates that the number of EHT-SIG symbols is one or more. For example, the subfield indicating the number of EHT-SIG symbols could be a subfield indicating the number of EHT-SIG symbols or MU-MIMO users, or it could be an EHT-SIG symbol count subfield.

[0201] Optionally, Bfee may obtain the sum of the lengths of all fields following the L-SIG based on the length indication information within the L-SIG, and then obtain the lengths of the RL-SIG, EHT-SIG, EHT-LTF, and PE fields based on the number of EHT-SIG symbols, EHT-LTFs, guard interval length, EHT-LTF size, and 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 within the L-SIG, and then calculate the number of symbols in the data field. If Bfee calculates that the length of the data field is 0 or less, Bfee identifies the PPDU as an NDP.

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

[0203] Furthermore, 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 half the code rate. As shown in Table 2, in a PPDU including the data field, the number of information bits for the EHT-SIG is 54. When the EHT-SIG is modulated using BPSK and half the code rate, the number of EHT-SIG symbols obtained through coding is greater than 1.

[0204] Thus, based on the subfield indicating the number of EHT-SIG symbols showing that the number of EHT-SIG symbols is 1, and the MCS subfield showing that the EHT-SIG is modulated using BPSK and half the code rate, 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 gain a longer processing time by pre-preparing the procedure for calculating channel state information, and does not need to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. Such an NDP helps improve the efficiency of Bfee in reading NDPs.

[0205] In one optional embodiment, the U-SIG further includes an NDP indication subfield and / or a PPDU format subfield. The NDP indication subfield or 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 understood that, in another optional embodiment, if the PPDU is in compressed mode, the EHT-SIG symbol count subfield in U-SIG indicates that the EHT-SIG symbol count is 1.

[0207] In another optional embodiment, the NDP's EHT-SIG includes common fields but does not include user-specific fields. Thus, the number of EHT-SIG symbols can be reduced by omitting user fields.

[0208] Specifically, as shown in Table 4, the NDP's EHT-SIG includes the number of EHT-LTF symbols, midamble periodicity, and doppler subfield, the preamble puncture indication subfield, the number of space-time streams (NSTS) subfield, the cyclic redundancy code (CRC), and the tail bit. The number of EHT-LTF symbols, midamble periodicity, and doppler subfield can 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 an NSS subfield. [Table 4]

[0209] The EHT-LTF symbol count, mid-amble periodicity, and Doppler subfields indicate the EHT-LTF symbol count, mid-amble periodicity, and Doppler. The preamble puncture indication subfield indicates the preamble puncture mode. The NSTS subfield indicates the spatiotemporal stream count or spatial stream count of the STA. Optionally, if spatiotemporal block coding is not considered, the NSTS subfield indicates 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 bit is 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 EHT-LTF symbol count, mid-amble periodicity, or Doppler subfield. Thus, some fields within the EHT-SIG may be omitted, and other information may be carried using the bits originally used to carry the omitted fields.

[0211] In one possible case, EHT-SIG includes the EHT-LTF symbol count, mid-amble periodicity, and Doppler subfield, but does not include the NSTS or NSS subfield. Thus, other information can be carried using bits (B12-B15) that were originally used to carry the NSTS or NSS subfield.

[0212] Specifically, among the EHT-LTF symbol count, mid-amble periodicity, and Doppler subfield, the portion that originally indicates the EHT-LTF symbol count can be used to indicate the EHT-LTF symbol count, or to indicate NSTS in escape mode. Based on the correspondence between the EHT-LTF symbol count and NSTS and between NSS and NSTS in the above-mentioned related explanation of the first type of NDP, the EHT-LTF symbol count, mid-amble periodicity, and Doppler subfield can indicate the EHT-LTF symbol count and NSTS, or the EHT-LTF symbol count and NSS, by indicating one of the EHT-LTF symbol count, NSTS, or NSS.

[0213] In another possible case, the EHT-SIG includes the NSTS subfield, but neither the NSS subfield nor the EHT-LTF symbol count, mid-amble periodicity, or Doppler subfield are included. Specifically, the NSTS subfield indicates NSTS and indirectly indicates NSS and the EHT-LTF symbol count based on the correspondence between the EHT-LTF symbol count and NSTS and between NSS and NSTS in the above-mentioned related explanation of the first type of NDP. Thus, other information can be carried using bits (B0-B3) that were originally used to carry the EHT-LTF symbol count, mid-amble periodicity, and Doppler subfield.

[0214] In another possible case, the EHT-SIG includes the NSS subfield, but neither the NSTS subfield nor the EHT-LTF symbol count, mid-amble periodicity, or Doppler subfield are included. Specifically, the NSS subfield indicates NSS and indirectly indicates NSTS and the EHT-LTF symbol count based on the correspondence between the EHT-LTF symbol count and NSTS, and between NSS and NSTS, as described above in the relevant explanation of the first type of NDP. Thus, other information can be carried using bits (B0-B3) that were originally used to carry the EHT-LTF symbol count, mid-amble periodicity, and Doppler subfield.

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

[0216] It is clear that in the second type of NDP provided in the embodiments of this application, there is only one EHT-SIG symbol, and therefore the overhead of the NDP is reduced while carrying sufficient information.

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

[0218] The third type of NDP provided in this embodiment of this application includes an EHT-SIG. The EHT-SIG includes a user field. The user field includes an AID subfield indicating the AID. Specifically, the EHT-SIG of the NDP includes a common field and a user-specific field. The common field indicates some common information, such as preamble indication information indicating the puncturing state 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 APs. Thus, Bfee can determine information about the NDP user based on the AID in the NDP's EHT-SIG. Thus, Bfee can accurately determine whether the Bfee is a user that needs to perform channel sounding and provide feedback on beamforming reports.

[0220] The following provides some embodiments in which the AID subfield indicates information about the NDP user.

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

[0222] Thus, a station corresponding to an AID can determine, based on the AID in the NDP, that it is a station that needs to perform channel sounding and provide feedback of a beamforming report based on the channel sounding results. Thus, even if a station fails to read the user field containing its AID because it does not correctly read the NDP frame, the station can still determine, based on the NDP, that it is a station that needs to perform channel sounding and provide feedback of a beamforming report based on the channel sounding results, thereby improving the success rate of Bfer obtaining beamforming reports. Furthermore, if a device that does not match the AID indicated by the AID subfield after receiving the NDP reads that the AID indicated by the AID subfield does not match the AID of that 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, if the NDP user is multiple stations, the AID indicated by the user field is 0, indicating that the NDP is transmitted via broadcast. In this embodiment, the EHT-SIG of the NDPA frame transmitted before the NDP includes multiple station fields, and the AID subfield within these multiple station fields indicates the AID of the station that needs to perform channel sounding and feed back beamforming reports. Thus, a station receives the NDP and determines that the NDP user is multiple stations based on the fact that the AID subfield of the NDP is 0.

[0224] Thus, all stations receiving the NDP, or the station corresponding to the AID indicated by the user field in the NDPA frame, continue to receive the NDP, acquire channel status information based on the NDP, and provide feedback of the beamforming report.

[0225] In some further embodiments, if the NDP user is an access point, the AID indicated by the AID subfield is a default value. The default value can be announced by the AP via broadcast, or it can be a fixed value pre-configured in the standard, such as 2045. It should be understood that the default value may be a different value instead.

[0226] Optionally, see Figure 11 for the structure of a third type of NDP provided in this embodiment of this application. This NDP further includes L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, EHT-STF, EHT-LTF, and PE fields. For the function of these subfields, see the relevant description of the first type of NDP provided in the above-described embodiment of this application. Further details will not be described again here.

[0227] It can be seen that the structure of the NDP is similar to the format of an EHT PPDU, which includes the data fields shown in Figure 5. Thus, Bfee can receive the NDP by using a similar receiving policy to that of an EHT PPDU, which includes the data fields.

[0228] For details on how Bfee identifies the PPDU version, please refer to the relevant description of how Bfee identifies the PPDU version in the above embodiments corresponding to the first type of NDP provided in this application. Further details will not be provided here.

[0229] As for how Bfee identifies that a PPDU is an NDP, using the method by which Bfee calculates the length of a data field in the above embodiment corresponding to a second type of NDP provided in this embodiment, the length of the data field can be calculated to be 0, and as a result Bfee identifies that the PPDU is an NDP.

[0230] In the third type of NDP provided in the embodiments of this application, several simpler indication schemes may be used instead to indicate that a PPDU is an NDP. Thus, Bfee can determine that a PPDU is an NDP in a simpler way, more quickly, and pre-prepare the procedure for calculating channel state information, thereby obtaining a longer processing time.

[0231] In one indication scheme for showing that a PPDU is an NDP, the U-SIG includes a format subfield and / or a compression subfield, and the format subfield or compression subfield within 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 compression subfield. Thus, by identifying the PPDU as an NDP before calculating that the number of symbols in the PPDU's data fields is zero, and by reading the PPDU based on the NDP format, Bfee can pre-prepare the procedure for calculating channel status information, gain a longer processing time, and improve NDP read efficiency.

[0232] The 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 NDP user, or it may be implemented independently.

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

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

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

[0236] In one optional embodiment, the number of EHT-LTFs is greater than the number of spatiotemporal streams. Thus, in an aggregated PPDU transmission scenario, when multiple NDPs, whose structure is the same as that of a 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 to align the symbols of the NDP fields and avoid out-of-band interference between different frequency bands.

[0237] In the embodiments provided in this application, the methods provided in the embodiments of this application are described separately from the viewpoint of an access point and a station. To implement the functions of the methods provided in the embodiments of this application, access points and stations may include hardware structures and software modules to implement the functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. One of the functions may be performed in the form of a hardware structure, in the form of a software module, or in a combination of hardware structures and software modules.

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

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

[0240] The transmitting unit 1202 is configured to transmit PPDU.

[0241] Thus, the Bfee receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG that indicates the PPDU is an NDP. Therefore, the Bfee can prepare the procedure for calculating channel state information in advance, thus gaining more processing time, and does not need to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps improve the efficiency of the Bfee in receiving NDPs.

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

[0243] In some embodiments, the PPDU further includes an ultra-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 EHT-SIG symbol count within the U-SIG.

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

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

[0247] The processing unit 1301 is configured to generate a PPDU, which is an NDP, which includes an ultra-high throughput signal field EHT-SIG, which has 1 EHT-SIG symbol, and which is modulated using BPSK and half the code rate.

[0248] The transmitting unit 1302 is configured to transmit PPDU.

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

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

[0251] 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 being one or more.

[0252] In some embodiments, a 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 / coding scheme MCS subfield, which indicates that the EHT-SIG is modulated using BPSK and a 1 / 2 code rate.

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

[0254] In some embodiments, a spatiotemporal stream number subfield and / or a subfield indicating the number of EHT-LTF symbols in the EHT-SIG indicates the spatiotemporal stream number and the number of EHT-LTF symbols.

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

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

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

[0258] Thus, Bfee can determine information about the NDP user based on the AID in the NDP's EHT-SIG. Thus, Bfee can accurately determine whether that Bfee is a user that needs to perform channel sounding and provide feedback on beamforming reports.

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

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

[0261] In some embodiments, if the NDP user is 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 NDP user 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, which includes a format subfield and / or a compression subfield, the format subfield or the compression subfield indicating that the PPDU is an NDP.

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

[0265] Figure 15 is a schematic diagram of a transmission device module according to one 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, which is an NDP, which includes a universal signaling field U-SIG, which 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 NDP.

[0268] A Bfee receiving the NDP can determine that the PPDU is an NDP based on the subfield in the U-SIG that indicates the PPDU is an NDP. Therefore, the Bfee can pre-prepare the procedure for calculating channel state information, thus gaining more processing time, and does not need to calculate that the length of the data portion of the PPDU is 0 before determining that the PPDU is an NDP. The NDP helps improve the efficiency of the Bfee in receiving NDPs.

[0269] The transmission device 1500 may be understood as a Bfee. The transmission device 1500 may be, for example, a station or an access point. Alternatively, the transmission device 1500 may be located at a station or 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 ultra-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 EHT-SIG symbol count within the U-SIG.

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

[0273] Figure 16 is a schematic diagram of a transmission device module according to one 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, which is an NDP, which includes an ultra-high throughput signal field EHT-SIG, which has 1 symbol, and which is modulated using BPSK and a 1 / 2 code rate.

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

[0276] In this way, the number of EHT-SIG symbols can be reduced, and thus the overhead required to transmit the NDP can be reduced.

[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 arranged 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, the U-SIG includes a subfield indicating the number of EHT-SIG symbols, and the subfield indicating the number of EHT-SIG symbols indicates that the number of EHT-SIG symbols is some value of 1 or more.

[0279] In some embodiments, the NDP indication subfield or the PPDU format subfield in the U-SIG indicates that the PPDU is in the non-compressed 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, and the MCS subfield indicates that the EHT-SIG is modulated using BPSK and a code rate of 1 / 2.

[0281] In some embodiments, the subfield indicating the number of spatial and temporal stream numbers and / or the subfield indicating the number of EHT-LTF symbols in the EHT-SIG indicates the number of spatial and temporal stream numbers and the number of EHT-LTF symbols.

[0282] Figure 17 is a schematic diagram of a transmission device module according to one 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, which is an NDP, which includes an ultra-high throughput signal field EHT-SIG, which has 1 symbol, and which is modulated using BPSK and a 1 / 2 code rate.

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

[0285] Thus, Bfee can determine information about the NDP user based on the AID in the NDP's EHT-SIG. Thus, Bfee can accurately determine whether that Bfee is a user that needs to perform channel sounding and provide feedback on beamforming reports.

[0286] The transmission device 1600 may be understood as a Bfee. The transmission device 1700 may be, for example, a station or an access point. Alternatively, the transmission device 1700 may be located at a station or access point. The processing unit 1702 of the transmission device 1700 may be a processor, and the receiving unit 1701 of the transmission device 1700 may be a transceiver.

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

[0288] In some embodiments, if the NDP user is 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 NDP user 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, which includes a format subfield and / or a compression subfield, the format subfield or the compression subfield indicating that the PPDU is an NDP.

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

[0292] For related content regarding the above-described embodiment of the transmission device, please refer to the related content regarding the above-described embodiment of the method. Further details will not be explained here.

[0293] This application further provides a computer-readable storage medium that stores a computer program. When the computer-readable storage medium is executed by a computer, the functionality of any of the embodiments of the method embodiments described above is implemented.

[0294] This application further provides a computer program product. When the computer program product is executed by a computer, the functionality of any of the embodiments of the method embodiments described above is implemented.

[0295] Furthermore, it should be understood that the terms “First,” “Second,” “Third,” “Fourth,” and various other numbers in this specification are used solely for the purpose of distinction for ease of explanation and should not 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 the relevant relationship for describing related objects and represents that three relationships may exist. For example, A and / or B may represent three cases where only A exists, both A and B exist, and only B exists. Also, the character " / " in this specification usually indicates an "or" relationship between related objects.

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

[0298] As those skilled in the art can recognize, 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 by a combination of computer software and electronic hardware. Whether the function is executed by hardware or by 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 it should not be considered that the implementation exceeds the scope of this application.

[0299] As those skilled in the art can clearly understand, for the purpose of a simple and concise description, for the detailed operation processes of the above-mentioned system, device, and unit, please refer to the corresponding processes in the above-mentioned method embodiments. Details will not be described here again.

[0300] In some embodiments provided in this application, it should be understood that the disclosed systems, apparatus, and methods may be implemented in other ways. For example, the described apparatus embodiments are merely examples. For example, unit division is merely a logical functional division and may be other divisions in actual implementation. For example, multiple units or components may be combined or integrated with other systems, or some mechanisms may be ignored or not performed. Also, the mutual coupling or direct coupling or communication connection shown or described may be implemented via some interface. Indirect coupling or communication connection between multiple devices or units may be implemented in an electrical, mechanical, or other form.

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

[0302] Furthermore, the 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 independently, or two or more units may be integrated into a single unit.

[0303] When functions are implemented in the form of software function units and sold or used as independent products, those functions may be stored in a computer-readable storage medium. Based on this understanding, the technical solutions in this application, or the parts that contribute to existing technologies, or parts of the technical solutions, may be implemented in the form of a software product. The computer software product is stored in a storage medium and includes several instructions that instruct a computer device (which may be a personal computer, server, or network device, or similar) to perform all or part of the steps of the method in the embodiments of this application. The storage medium mentioned above includes any medium capable of storing program code, such as a USB flash drive, removable hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0304] The steps of the method in the embodiments of this application may be modified, combined, and deleted based on actual requirements.

[0305] Modules within the apparatus in the embodiments of this application may be combined, separated, and removed based on actual requirements.

[0306] Finally, the embodiments described above are intended merely to illustrate the technical solutions of this application and not to limit it. Although this application is described in detail with reference to the embodiments described above, it should be understood that those skilled in the art can still modify the technical solutions described in the embodiments described above, or substitute some of their technical features with equivalent ones, without departing from the scope of the technical solutions of the embodiments of this application.

Claims

1. A PPDU transmission method, The receiving of a Physical Layer Protocol Data Unit (PPDU) is provided, the PPDU not containing a data field, but containing an Ultra-High Throughput Signal (EHT-SIG) field and a Universal Signal (U-SIG) field, wherein the U-SIG field includes a subfield indicating that the EHT-SIG field has 1 symbol, and a subfield indicating that the EHT-SIG field is modulated using Dual Phase Shift Modulation (BPSK) and a 1 / 2 code rate. Identifying that the PPDU is a null data packet (NDP) according to 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, By using the aforementioned NDP, channel estimation is performed, A method of having.

2. The method according to claim 1, wherein the NDP indication subfield or PPDU format subfield in the U-SIG field indicates that the PPDU is in uncompressed mode.

3. The method according to claim 1 or 2, wherein the PPDU further includes an ultra-high throughput long training (EHT-LTF) field, and the EHT-SIG field further includes a subfield indicating the number of spatial streams and a subfield indicating the number of symbols in the EHT-LTF field.

4. A method for transmitting physical layer protocol data units (PPDUs), The method involves generating a Physical Layer Protocol Data Unit (PPDU), which does not contain a data field and is a null data packet (NDP), and which includes an Ultra-High Throughput Signal (EHT-SIG) field and a Universal Signal (U-SIG) field, wherein the U-SIG field includes a subfield indicating that the number of symbols in the EHT-SIG field is 1, and a subfield indicating that the EHT-SIG field is modulated using Dual Phase Shift Modulation (BPSK) and a 1 / 2 code rate. Transmitting the aforementioned PPDU, A method of having.

5. The method according to claim 4, wherein the NDP indication subfield or PPDU format subfield in the U-SIG field indicates that the PPDU is in uncompressed mode.

6. The method according to claim 4 or 5, wherein the PPDU further includes an ultra-high throughput long training (EHT-LTF) field, and the EHT-SIG field further includes a subfield indicating the number of spatial streams and a subfield indicating the number of symbols in the EHT-LTF field.

7. It is an access point, A receiving unit used to receive a Physical Layer Protocol Data Unit (PPDU), wherein the PPDU does not include a data field and includes an Ultra-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, and a subfield indicating that the EHT-SIG field is modulated using Dual Phase Shift Modulation (BPSK) and a 1 / 2 code rate, and It is a processing unit, The PPDU is identified as a null data packet (NDP) according to 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. Channel estimation is performed using the aforementioned NDP. A processing unit used in particular, An access point having

8. The access point according to claim 7, wherein the NDP indication subfield or PPDU format subfield in the U-SIG field indicates that the PPDU is in uncompressed mode.

9. The access point according to claim 7 or 8, wherein the PPDU further includes an ultra-high throughput long training (EHT-LTF) field, and the EHT-SIG field further includes a subfield indicating the number of spatial streams and a subfield indicating the number of symbols in the EHT-LTF field.

10. It is an access point, A processing unit used to generate a Physical Layer Protocol Data Unit (PPDU), the PPDU being a null data packet (NDP) and not containing a data field, the PPDU including an Ultra-High Throughput Signal (EHT-SIG) field and a Universal Signal (U-SIG) field, the U-SIG field including a subfield indicating that the EHT-SIG field has 1 symbol, and a subfield indicating that the EHT-SIG field is modulated using Dual Phase Shift Modulation (BPSK) and a 1 / 2 code rate, A transmitting unit used to transmit the PPDU, An access point having

11. The access point according to claim 10, wherein the NDP indication subfield or PPDU format subfield in the U-SIG field indicates that the PPDU is in uncompressed mode.

12. The access point according to claim 10 or 11, wherein the PPDU further includes an ultra-high throughput long training (EHT-LTF) field, and the EHT-SIG field further includes a subfield indicating the number of spatial streams and a subfield indicating the number of symbols in the EHT-LTF field.

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