Triggered detection NDP

Abstract

The present disclosure relates to a method of uplink sounding signal triggering performed by an access point (AP), comprising the steps of: transmitting, by the AP, a trigger signal to one or more stations (STAs) to trigger transmission of a corresponding sounding signal from at least one of the one or more STAs in response to the trigger signal; receiving, by the AP, a respective sounding signal from the at least one STA; determining, by the AP, a precoder to be used by the at least one STA based on the corresponding probe signal, and transmitting corresponding precoder information to the at least one STA for data transmission; wherein the trigger signal comprises a null data packet announcement (NDPA) signal or a null data packet request (NDPR) signal, and the probe signal comprises a triggered probe null data packet (NDP) signal; wherein the triggered sounding (NDP) signal is based on a TB physical protocol data unit (PPDU) frame without a payload or based on a very high throughput (EHT) multi-user (MU) PPDU frame without a payload; and wherein the U-SIG portion of the TB PPDU frame or the EHT MU PPDU frame of the Triggered Sounding NDP signal comprises a parameter indicating the Triggered NDP transmission.

Description

Technical Field

[0001] The invention relates to a method for triggering an uplink detection signal. Background Art

[0002] Beamforming (BF) is widely used in Wi-Fi communications as a successful technique to improve performance in MIMO scenarios. Beamforming is a process by which the sender of a transmission can send a signal to the receiver in a preferred direction to improve the signal-to-noise ratio and transmission speed. In general, beamforming can be divided into two main types. Explicit beamforming is based on exchanging information about the characteristics of the radio channel between the transmitter and the receiver to extract improved performance from the radio channel based on channel quality measurements, while in implicit beamforming, the measurement frame is sent by the beam receiver instead of the beamformer. The beamformer detects the frame and uses it for channel estimation while assuming reciprocity between the downlink channel and the uplink channel. The baseband digital signal varies depending on the channel. Beamforming has been supported since 802.11n.

[0003] In 802.11n, multiple sounding mechanisms are defined to support BF operation (e.g., implicit sounding using uplink signals, assuming reciprocity, to determine beamforming weights or precoders; and explicit sounding of transmission-specific signals so that the intended receiver (i.e., beamformer) can calculate precoding weights).

[0004] Beamforming in 802.11n requires two devices to implement mutually recognized beamforming functions. 802.11ac specifies a maximum of eight spatial streams for an access point (AP), compared to 802.11n which specifies only four spatial streams. Multiple spatial streams can be used to send to multiple clients simultaneously.

[0005] In 802.11ac and 802.11ax, explicit probing is the only mechanism defined to support BF operation.

[0006] Both downlink (DL) and uplink (UL) support beamforming.

[0007] DL beamforming is completely managed by the access point AP, and the precoder can be adjusted based on the currently scheduled transmission. Different transmission schemes may require different precoders to achieve better performance. The AP collects feedback information from different sites and can calculate the relevant precoder optimized for a specific packet.

[0008] In UL, the same process is applied, but the station (STA) acts as a beamformer and therefore triggers the process and collects precoder feedback from the beam receiver (here AP). This means that the STA saves the precoder information and decides which precoder to apply when.

[0009] According to the existing protocol in 802.11ax, UL BF is supported by the following: the STA sends an NDP Announcement (NDP-A) frame before the Null Data Packet (NDP), followed by the AP response with a Beamforming Report (BFR).

[0010] A new feature in 802.11ax (compared to earlier 802.11 standards) is the introduction of a Trigger Frame (TF), which instructs the intended receiver (usually a STA) to transmit in response to receiving a TF.

[0011] However, there is a lack of suitable formats for UL BF using triggered transmission. Summary of the invention

[0012] In view of the above, an object of the present disclosure is to at least partially overcome the above disadvantages and enable setting of Tx parameters of TB PPDU by AP for triggered sounding NDP in UL.

[0013] The aforementioned objects and other objects are achieved by the subject matter of the independent claims. Other implementations are apparent from the dependent claims, the description and the drawings.

[0014] According to a first aspect, a method for uplink sounding signal triggering performed by an access point (AP) is provided, the method comprising the following steps: sending a trigger signal by the AP to one or more stations (STA), thereby triggering the transmission of a corresponding sounding signal from at least one of the one or more STAs in response to the trigger signal; receiving the corresponding sounding signal by the AP from the at least one STA; and determining by the AP a precoder to be used by the at least one STA based on the corresponding sounding signal, and sending corresponding precoder information to the at least one STA for data transmission; wherein the trigger signal comprises a Null Data Packet Announcement (NDPA) signal or a Null Data Packet Request (NDPR) signal, and the sounding signal comprises a triggered sounding Null Data Packet (NDP) signal; wherein the triggered sounding NDP signal is based on a trigger-based (TB) physical protocol data unit (PPDU) frame without a payload or based on an extremely high throughput (EHTU) frame without a payload. The invention relates to a multi-user (MU) PPDU frame having a triggered sounding NDP signal and a U-SIG portion of the TB PPDU frame or the EHT MU PPDU frame having a triggered sounding NDP signal; and wherein the U-SIG portion of the TB PPDU frame or the EHT MU PPDU frame of the triggered sounding NDP signal includes a parameter indicating a triggered NDP transmission. Here, the optional EHT-SIG portion of the EHT MU PPDU frame of the triggered sounding NDP signal may be omitted.

[0015] The present disclosure provides a U-SIG portion of a TB PPDU or a U-SIG portion of an EHT MU PPDU frame of a triggered sounding NDP signal, the U-SIG portion including parameters indicating a triggered NDP transmission. Therefore, the AP can know that the transmission is a triggered NDP transmission. The "triggered sounding NDP" signal is a signal of a new format, which is different from the traditional sounding NDP signal. When using a triggered sounding NDP of a new format (a variant of an existing PPDU type), no payload is involved, and STA identification may be performed by using the physical properties of the transmitted signal (e.g., the power of the estimated channel of each triggered source).

[0016] Depending on the implementation, the PPDU type of the triggered sounding NDP signal - TB PPDU or EHT MU PPDU, and / or PPDU variant is indicated in the PPDU type and compression mode fields in the U-SIG part. Here, Option 1 is a new variant of the TB PPDU type with a different U-SIG design, and Option 2 is a new variant of the EHT MU PPDU with a different U-SIG design and an optional EHT-SIG field (redundant for triggered transmission). Both options enable the following properties: ensuring that all STAs send the same preamble content, recognizing that this is a requested NDP transmission (avoiding hidden nodes or interference sources), and allowing the AP to reuse the detector of the TB PPDU.

[0017] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 2 or 3.

[0018] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 0, and B2 of U-SIG-2 may be set to 1 to indicate a triggered sounding NDP.

[0019] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 0, and a combination of 11 ignored bits of the U-SIG may be used to indicate a triggered sounding NDP.

[0020] According to an implementation, the U-SIG portion of the triggered sounding NDP signal includes a UL / DL field that can be set to 1.

[0021] According to an implementation, the U-SIG part of the triggered sounding NDP signal may include a spatial reuse field, and the spatial reuse field is reserved or set to not allowed, so that spatial reuse is not allowed when indicating the triggered NDP transmission.

[0022] According to implementation, the bandwidth (BW) indicated in the U-SIG part of the triggered sounding NDP may be the same as the BW indicated by the NDPA or NDPR trigger signal.

[0023] According to implementation, the puncturing channel information field of the U-SIG part may be reserved.

[0024] According to implementation, the EHT-SIG symbol quantity indication field of the U-SIG part may be reserved.

[0025] According to the U-SIG design of Option 1 with triggered sounding NDP as an EHT TB PPDU variant, one or more changes to the U-SIG design may be introduced, as defined in the above implementation: UL / DL should be set to "1", and / or BW should be the same as indicated by NDPR, and / or if triggered NDP is indicated, spatial reuse is not allowed, so the spatial reuse field may be set to "Not Allowed" or may be reserved.

[0026] According to the U-SIG design of Option 2 with triggered sounding NDP as an EHT MU PPDU variant, one or more changes to the U-SIG design may be introduced, as defined in the above implementations: the triggered NDP does not require puncturing channel information - i.e., the field is reserved, and / or the EHT-SIG symbol number is always 1 - i.e., the field is reserved, and / or UL / DL is set to "1", and / or the BW is the same as indicated by the NDPR.

[0027] According to a second aspect, a method for uplink sounding signal triggering performed by a station (STA) is provided, the method comprising the following steps: receiving a trigger signal from an access point (AP) by the STA; sending a sounding signal from the STA to the AP in response to the trigger signal; receiving, by the STA, from the AP precoder information corresponding to a precoder to be used by the STA determined by the AP based on the sounding signal for data transmission; wherein the trigger signal comprises a Null Data Packet Announcement (NDPA) signal or a Null Data Packet Request (NDPR) signal, and the sounding signal comprises a triggered sounding Null Data Packet (NDP) signal; wherein the triggered sounding NDP signal is based on a trigger-based (TB) physical protocol data unit (PPDU) frame without a payload or based on an extremely high throughput (EHT) multi-user (MUL) frame without a payload. wherein the U-SIG part of the TB PPDU or EHT MU PPDU frame of the triggered detection NDP signal includes a parameter indicating the triggered NDP transmission.

[0028] The descriptions and advantages provided above are relatively applicable here. In order to avoid repetition, these contents will be omitted here and below.

[0029] Depending on the implementation, the PPDU type of the triggered sounding NDP signal, TB PPDU or EHT MU PPDU, and / or PPDU variant may be indicated in the PPDU type and compression mode fields in the U-SIG part.

[0030] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 2 or 3.

[0031] Depending on the implementation, the PPDU Type and Compression Mode fields are set to 0, and B2 of U-SIG-2 may be set to 1 to indicate a triggered sounding NDP.

[0032] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 0, and a combination of 11 ignored bits of the U-SIG may be used to indicate a triggered sounding NDP.

[0033] Depending on the implementation, the U-SIG portion of the triggered sounding NDP signal may include a UL / DL field set to 1.

[0034] According to an implementation, the U-SIG part of the triggered sounding NDP signal may include a spatial reuse field, and the spatial reuse field is reserved or set to not allowed, so that spatial reuse is not allowed when indicating the triggered NDP transmission.

[0035] According to implementation, the bandwidth (BW) indicated in the U-SIG part of the triggered sounding NDP may be the same as the BW indicated by the NDPA or NDPR trigger signal.

[0036] According to implementation, the puncturing channel information field of the U-SIG part may be reserved.

[0037] According to implementation, the EHT-SIG symbol quantity indication field of the U-SIG part may be reserved.

[0038] According to a third aspect, a method for uplink sounding signal triggering performed by an access point (AP) is provided, the method comprising the following steps: the AP sends a trigger signal to one or more stations (STA), thereby triggering the transmission of a corresponding sounding signal from at least one of the one or more STAs in response to the trigger signal; the AP receives the corresponding sounding signal from the at least one STA; and the AP determines a precoder to be used by the at least one STA based on the corresponding sounding signal, and sends corresponding precoder information to the at least one STA for data transmission; wherein the trigger signal comprises a Null Data Packet Announcement (NDPA) signal or a Null Data Packet Request (NDPR) signal, and the sounding signal comprises a triggered sounding Null Data Packet (NDP) signal; wherein the triggered sounding NDP signal is based on an Extremely High Throughput (EHT) trigger-based (TB) physical protocol data unit (Physical Protocol Data Unit) including a data portion. Unit, PPDU) frame; and wherein the EHT TB PPDU frame sends K spatial streams (SS) in an EHT long training field (LTF) part and sends N SSs in the data part, and the EHT TB PPDU frame is configured to allow K to be independent of N.

[0039] Therefore, the present disclosure enables the EHT TB PPDU frame to be configured to allow the number K of spatial streams (SS) in the EHT Long Training Field (LTF) portion to be independent of the number N of SSs in the data portion. In other words, the number N does not define the number K by a fixed relationship.

[0040] Such modification to the TB PPDU transmission rule supports the case where the number of transmit (Tx) antennas is greater than the number of supported SSs.

[0041] According to the implementation, the number K of spatial streams (SS) in the EHT Long Training Field (LTF) part may depend on the number M of transmit antennas.

[0042] According to an implementation, the EHT LTF part may include EHT LTF OFDM symbols, and the number K of EHT LTF OFDM symbols is the number K of transmitting antennas indicated by the at least one STA in the capability report.

[0043] According to implementation, the AP may indicate, through the NDPA signal, which subset of transmit antennas the at least one STA will use for transmission.

[0044] According to implementation, the triggered sounding NDP may be received by the AP from a subset of transmit antennas of the at least one STA.

[0045] According to implementation, the PPDU type of the triggered sounding NDP signal, EHT MU PPDU, and / or PPDU variant, may be indicated in the PPDU type and compression mode fields in the U-SIG part.

[0046] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 2 or 3.

[0047] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 0, and B2 of U-SIG-2 may be set to 1 to indicate a triggered sounding NDP.

[0048] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 0, and a combination of 11 ignored bits of the U-SIG may be used to indicate a triggered sounding NDP.

[0049] Therefore, in this aspect, and according to Option 1, a new variant of the TB PPDU type is provided, in which the number of SSs in the EHT LTF (K) and the number of SSs in the data part (N) are independent of each other. In an exemplary case, the data part will be sent with a single SS (N=1) that is replicated for all antennas, and K will depend on the number of Tx antennas indicated by the STA in the capability report.

[0050] According to Option 2, a new variant of the TB PPDU type is provided, in which the selected Tx antenna is indicated by the NDPR. The AP can indicate which subset of Tx antennas should be used for transmission, and the STA will transmit using the indicated subset (in this case, K can be less than or equal to the number of supported SSs for data transmission).

[0051] According to a fourth aspect, a method for uplink sounding signal triggering performed by a station (STA) is provided, the method comprising the following steps: receiving a trigger signal from an access point (AP) by the station (STA); sending a sounding signal from the STA to the AP in response to the trigger signal; and receiving, by the STA, from the AP precoder information corresponding to a precoder to be used by the STA determined by the AP based on the sounding signal for data transmission; wherein the trigger signal comprises a Null Data Packet Announcement (NDPA) signal or a Null Data Packet Request (NDPR) signal, and the sounding signal comprises a triggered sounding Null Data Packet (NDP) signal; wherein the triggered sounding NDP signal is based on an Extremely High Throughput (EHT) Trigger Based (TB) Physical Protocol Data Unit (PPDU) frame including a data portion; and wherein the EHT TB PPDU frame is in an EHT Long Training field (LTF) In the EHT TB PPDU frame, K spatial streams (SS) are sent in the LTF (Transmitted Time Field) part and N SSs are sent in the data part, and the EHT TB PPDU frame is configured to allow K to be independent of N.

[0052] The descriptions and advantages described above are relatively applicable here. In order to avoid repetition, these contents will be omitted here and below.

[0053] According to the implementation, the number K of spatial streams (SS) in the EHT Long Training Field (LTF) part depends on the number M of transmit antennas.

[0054] According to an implementation, the EHT LTF part includes EHT LTF OFDM symbols, and the number K of EHT LTF OFDM symbols is the number K of transmitting antennas indicated by the at least one STA in the capability report.

[0055] According to implementation, the AP may indicate, through the NDPA signal, which subset of transmit antennas the at least one STA will use for transmission.

[0056] According to implementation, the triggered sounding NDP may be received by the AP from a subset of transmit antennas of the at least one STA.

[0057] According to implementation, the PPDU type of the triggered sounding NDP signal, EHT MU PPDU, and / or PPDU variant, may be indicated in the PPDU type and compression mode fields in the U-SIG part.

[0058] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 2 or 3.

[0059] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 0, and B2 of U-SIG-2 may be set to 1 to indicate a triggered sounding NDP.

[0060] Depending on the implementation, the PPDU Type and Compression Mode fields may be set to 0, and a combination of 11 ignored bits of the U-SIG may be used to indicate a triggered sounding NDP.

[0061] According to a fifth aspect, an access point (AP) is provided, the AP comprising a processing circuit configured to execute a method triggered by an uplink detection signal performed by the above-mentioned access point (AP) or any implementation thereof.

[0062] According to a sixth aspect, a station (STA) is provided, the STA comprising a processing circuit configured to execute the uplink detection signal triggered method performed by the above-mentioned station (STA) or any implementation thereof.

[0063] According to a seventh aspect, a computer program is provided, the computer program comprising instructions, which, when executed by a computer, cause the computer to perform any of the above-mentioned uplink sounding signal triggered methods.

[0064] According to a sixth aspect, a computer-readable medium is provided, the computer-readable medium comprising instructions, which, when executed by a computer, cause the computer to perform any of the above-mentioned uplink detection signal triggering methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In the following, embodiments of the present disclosure are described in more detail with reference to the accompanying drawings, in which:

[0066] Figure 1 An uplink UL beamforming scheme is shown.

[0067] Figure 2 The EHT NDP format is shown.

[0068] Figure 3A and Figure 3B An indication of the PPDU type and variant is shown.

[0069] Figure 4 The TB ranging NDP in 802.11az is shown.

[0070] Figure 5 An EHT TB PPDU variant of a triggered sounding NDP is shown.

[0071] Figure 6 An EHT MU PPDU variant of the triggered sounding NDP is shown.

[0072] Figure 7 A method according to the first aspect is shown being performed by an AP.

[0073] Figure 8 The U-SIG design of the new TB PPDU variant is shown.

[0074] Fig. 9 The U-SIG design of the new EHT MU PPDU variant is shown.

[0075] Fig.10 A method according to the second aspect is shown being performed by a STA.

[0076] Fig.11 A method according to the third aspect is shown being performed by an AP.

[0077] Fig.12 The U-SIG design of the new EHT TB PPDU variant is shown.

[0078] Fig.13 A method according to the fourth aspect performed by a STA is shown.

[0079] Fig.14 The Tx antenna PHY elements are shown.

[0080] Fig.15 An AP according to a fifth aspect is shown.

[0081] Fig.16 A STA according to the sixth aspect is shown.

[0082] Fig.17 The simulation results are shown. DETAILED DESCRIPTION

[0083] In the following description, reference is made to the accompanying drawings that form a part of the present disclosure, which illustrate by way of illustration specific aspects of the embodiments of the present disclosure or specific aspects of the embodiments of the present disclosure that can be used. It should be understood that the embodiments of the present disclosure can be used in other aspects and include structural or logical changes not depicted in the drawings. Therefore, the following detailed description should not be understood in a restrictive sense, and the scope of the present disclosure is defined by the appended claims.

[0084] For example, it should be understood that the disclosure related to describing a method also applies to a corresponding device or system configured to perform the method, and vice versa. For example, if one or more specific method steps are described, the corresponding device may include one or more units such as functional units (e.g., one unit performs one or more steps, or multiple units each perform one or more steps in multiple steps) for performing the described one or more method steps, even if such one or more units are not explicitly described or shown in the drawings. On the other hand, for example, if a specific device is described based on one or more units (e.g., functional units), the corresponding method may include a step for performing the function of one or more units (e.g., one step performs the function of one or more units, or multiple steps each perform the function of one or more units in multiple units), even if such one or more steps are not explicitly described or shown in the drawings. In addition, it should be understood that unless otherwise explicitly stated, the features of the various exemplary embodiments and / or aspects described herein may be combined with each other.

[0085] Other implementation details and advantages compared to the prior art are described below.

[0086] Figure 1A general concept 100 of initializing data upload from one or more stations (STAs) 111, 112, 113 to an access point (AP) 121 is shown, starting with a Null Data Packet Request Trigger Frame (NDPR TF) 131 sent by the AP 121 to the STAs 111, 112, 113 and corresponding Null Data Packets (NDPs) 141, 142, 143 sent in response by one or more STAs 111, 112, 113 to the AP 121. The NDPs 141, 142, 143 are packets containing a preamble (including a Long Training Field (LTF)) and can be used to estimate the physical channel between the AP 121 and the STAs 111, 112, 113. The NDP 141, 142, 143 may be sent simultaneously by several STAs 111, 112, 113. To perform beamforming, these NDP signals 141, 142, 143 are used by the AP 121 to determine precoding information. Thereafter, a basic TF 132 including a beamforming report (BFR) is sent to the STAs 111, 112, 113. The basic TF 132 is a frame that carries beamforming / precoding information such as precoding vectors or matrices, SNR corresponding to each precoder, etc. Upon receiving the basic TF 132, the STAs 111, 112, 113 start sending beamforming data 151, 152, 153 to the AP 121 in the UL. The AP 121 confirms the reception of the data block using a block data acknowledgment BA frame 133.

[0087] According to the prior art, a Null Data Packet (NDP) can be used as a frame for the detection process, which is sent by the same source that sends the NPD announcement (NDPA) frame immediately after the NPD announcement (NDPA) frame. The structure of the EHT NDP belongs to the EHT MU PPDU type, which is mainly used for transmissions not requested by the receiver (i.e., non-triggered transmissions). The PHY Protocol Data Unit (PPDU) sent in response to receiving a trigger frame (TF) is called a trigger-based (TB) PPDU. STA111, 112, 113 that is triggered to transmit in the UL is called a triggered STA. In the TB PPDU transmission, all transmission (transmit, Tx) parameters of the TB PPDU are set by AP 121, and AP 121 identifies each transmitter 111, 112, 113 via the decoded payload (e.g., MAC header).

[0088] like Figure 2 As shown, the EHT NDP preamble 200 includes a Universal Signal (U-SIG) 210 and an Extremely High Throughput Signal (EHT-SIG) 220, wherein the EHT-SIG 220 has only U-SIG overflow bits 211 (bits belonging to the U-SIG 210 but located at the EHT-SIG 220 due to the limited U-SIG size).

[0089] In addition, in 802.11be (EHT), there are two main PPDU types: EHT MU PPDU type and TB PPDU type. All PPDUs are sent using one of these types. In addition, EHT defines several variants of these types. The variants reuse the same structure of the PPDU type, but may differ in the meaning of specific fields or the number of specific parameters.

[0090] Figure 3A and Figure 3BIt is shown that the EHT PPDU type and variant are indicated in the U-SIG of the SIG field information 310 by a field named PPDU type and compression mode 311 (two bits) and a field named DL / UL (one bit) 312. Download is indicated by "0" represented by 312a, and upload is indicated by "1" represented by 312b. For upload, the PPDU type and compression mode field values ​​"0" represented by 311a and "1" represented by 311b indicate PPDU types EHT TB and EHT MU, respectively, while the values ​​"2" and "3" represented by 311c are currently not used.

[0091] As mentioned above Figure 1 As described above, in UL BF, NDPs 141, 142, 143 are sent by STAs 111, 112, 113 triggered by AP 121. However, there are differences between the current TB PPDU attributes and the NDP format, as described below.

[0092] Currently, the TB PPDU has two main properties, namely (i) all Tx parameters are set by AP 121 - this ensures alignment between all STAs 111, 112, 113, and therefore the preamble of the TB PPDU can be detected by a third receiver, and since the AP defines these parameters, the detection of the preamble can be skipped; and (ii) AP 121 identifies each transmitter 111, 112, 113 via the decoded payload (e.g., MAC header), i.e., successful reception of the data payload sent by STA111, 112, 113 enables AP 121 to identify the transmitter with an extremely low probability of error.

[0093] However, in the UL BF case where multi-user NDP transmission is triggered by AP 121, the current format of the NDP does not enable the same properties to be achieved.

[0094] Therefore, a new NDP design or an alternative solution is desired that enables the same properties to be achieved in UL BF triggered probing NDP.

[0095] In the 802.11az standard, a TB PPDU is used, and the AP 121 triggers a plurality of STAs 111 , 112 , 113 to transmit an NDP frame, and the STAs 111 , 112 , 113 transmit a TB PPDU without a payload. Figure 4 An NDP frame 400 is shown in the form of a TBPPDU 400 without a data field.

[0096] Although the TB PPDU without payload achieves alignment between multiple STAs 111, 112, 113, the TB PPDU without payload 400 has the disadvantage of no robust STA 111, 112, 113 identification (which is less important for the purpose of 802.11az), making the TB PPDU of 802.11az not robust enough in beamforming.

[0097] Therefore, it can be seen that the format used by 802.11az cannot provide the required properties.

[0098] A simple approach that can be considered in this regard is to use a regular TB PPDU with some short payload instead of NDP. This may solve the identification problem and the alignment problem between STAs 111, 112, 113.

[0099] However, this approach also has disadvantages and related issues involved. Some STAs 111, 112, 113 may have more transmit antennas than the number of supported spatial streams (SS) in ULTB transmission. The TB PPDU format forces the number of SSs in the EHT LTF part to be equal to the number of SSs in the data part. Therefore, such STAs 111, 112, 113 cannot transmit from all Tx antennas. This results in partial channel matrix estimation at the AP, resulting in inaccurate beamforming precoders.

[0100] As can be seen, there are several formats that provide partial solutions to the problem, however, in order to fully achieve the target properties of alignment and identification, the present disclosure proposes to modify / change the design of NDP and TB PPDU.

[0101] Figure 5 A conventional preamble 500 of a TB PPDU is shown with a U-SIG field 510. In addition, Figure 6 A conventional preamble 600 of a TB PPDU is shown with a U-SIG field 610 and an optional EHT-SIG field 620 (redundant for triggered transmission).

[0102] According to the present disclosure, the regular preamble of the TBPPDU is reused since some fields are irrelevant and can be redesigned for UL BF.

[0103] The main concept of the present disclosure is a new format of triggered NDP and TB PPDU that can support the requirements of UL BF protocol.

[0104] Two general possibilities are disclosed. The method according to the first and second aspects provides a new format (a variant of the existing PPDU type) for the triggered sounding NDP (in this method, there is no payload and STA identification can be done by the power of the estimated channel of each triggered source (Spatial Stream (SS)), see also Fig.17 The method according to the third aspect and the fourth aspect provides a modification to the TB PPDU transmission rule to support the case where the number of Tx antennas is greater than the number of supported SSs.

[0105] Both approaches provide solutions to the above problems.

[0106] Figure 7 (See also Figure 1 , Figure 8 and Fig. 9 ) shows a general representation of the uplink detection signal triggered method according to the first aspect performed by an access point (AP) 121 according to the first aspect of the present disclosure, comprising the following steps:

[0107] 701: The AP 121 sends a trigger signal to one or more stations (STAs) 111, 112, 113, thereby triggering the transmission of a corresponding detection signal from at least one STA 111, 112, 113 of the one or more STAs 111, 112, 113 in response to the trigger signal;

[0108] 702: The AP 121 receives a corresponding detection signal from at least one STA 111, 112, 113; and

[0109] 703: The AP 121 determines a precoder to be used by at least one STA 111, 112, 113 based on the corresponding sounding signal, and sends corresponding precoder information to at least one STA 111, 112, 113 for data transmission;

[0110] 704: wherein the trigger signal includes a Null Data Packet Announcement (NDPA) signal or a Null Data Packet Request (NDPR) signal, and the detection signal includes a triggered detection Null Data Packet (NDP) signal; wherein the triggered detection NDP signal is based on a trigger-based (TB) physical protocol data unit (PPDU) frame 800 without a payload or an extremely high throughput (EHT) multi-user (MU) PPDU frame 900 without a payload; and wherein the U-SIG part 810, 910 of the TB PPDU or EHT MU PPDU frame of the triggered detection NDP signal includes parameters indicating a triggered NDP transmission.

[0111] The U-SIG portion 310, 311a, 510, 810 of the TB PPDU frame 500 or the U-SIG portion 310, 311b, 610, 620, 910 of the EHT MUPPDU frame 600 of the triggered sounding NDP signal includes a parameter indicating the triggered NDP transmission (see FIG. 3, Figure 5 , Figure 6 , Figure 8 and Fig. 9 ). Therefore, AP 121 can know that the transmission is a triggered NDP transmission. The "triggered detection NDP" signal is a signal of a new format, which is different from the traditional detection NDP signal. Using the new format of the triggered detection NDP (a variant of the existing PPDU type), no payload is involved, and STA identification may be performed by using the physical properties of the transmitted signal (for example, the power of the estimated channel of each triggered source) (see Fig.17 ).

[0112] The advantage is that it ensures that all STAs 111, 112, 113 send the same preamble content, recognize that this is a requested NDP transmission (avoiding hidden nodes or interference), and enables the AP 121 to reuse the detector of the TB PPDU.

[0113] The general approach includes two options, one of which provides a new variant 500 of the TB PPDU type with a different U-SIG design 510 (e.g., based on Figure 5 ), another option provides a new variant 600 of the EHT MU PPDU with a different U-SIG design 610 and an optional EHT-SIG field 620 (e.g., based on Figure 6 ).

[0114] Figure 8 A first embodiment is shown, relating to a triggered sounding NDP 800 as a variant of the EHT TB PPDU. Several variations may be made to the U-SIG design 810, for example, UL / DL 812 is set to "1", and BW 813 is the same as indicated by the NDPR. If a triggered NDP is indicated, spatial reuse is not allowed, so the spatial reuse field 814 may be set to "Not Allowed" or may be reserved. Field 811 indicates the PPDU mode and compression type.

[0115] Fig. 9 A second embodiment is shown, relating to a triggered sounding NDP 900 as an EHT MU PPDU variant. Field 911 indicates the PPDU mode and compression type. Several changes may be made to the U-SIG design 910, for example, the triggered NDP does not require Puncturing Channel Information 915, so that the corresponding field is reserved, the EHT-SIG symbol number is always 1 and the corresponding field 916 is reserved, UL / DL 912 should be set to "1" and BW 913 should be the same as indicated by the NDPR.

[0116] Fig.10 (See also Figure 1 ) shows a general method for uplink sounding signal triggering performed by STAs 111, 112, and 113 according to the second aspect, comprising the following steps:

[0117] 1001: STAs 111, 112, and 113 receive a trigger signal from an access point (AP) 121;

[0118] 1002: In response to the trigger signal, STAs 111, 112, and 113 send a detection signal to AP 121; and

[0119] 1003: STAs 111, 112, 113 receive, from AP 121, precoder information corresponding to a precoder to be used by STAs 111, 112, 113, determined by the AP based on the sounding signal, for data transmission;

[0120] 1004: wherein the trigger signal includes a Null Data Packet Announcement (NDPA) signal or a Null Data Packet Request (NDPR) signal, and the detection signal includes a triggered detection Null Data Packet (NDP) signal; wherein the triggered detection NDP signal is based on a trigger-based (TB) physical protocol data unit (PPDU) frame 800 without a payload or based on an extremely high throughput (EHT) multi-user (MU) PPDU frame 900 without a payload; and wherein the U-SIG part 810, 910 of the TB PPDU or EHT MUPPDU frame of the triggered detection NDP signal includes parameters indicating a triggered NDP transmission.

[0121] This corresponds to the method according to the corresponding embodiment ( Figure 8 and Fig. 9 ) is a general method of the first aspect.

[0122] Fig.11 It is shown (also see Figure 1 and Fig.12 ) A general method of uplink sounding signal triggering performed by AP 121 according to the third aspect comprises the following steps:

[0123] 1101: AP 121 sends a trigger signal to one or more stations (STAs), thereby triggering transmission of a corresponding detection signal from at least one STA among the one or more STAs 111, 112, and 113 in response to the trigger signal;

[0124] 1102: The AP 121 receives a corresponding detection signal from at least one STA 111, 112, 113; and

[0125] 1103: The AP 121 determines a precoder to be used by at least one STA 111, 112, 113 based on the corresponding sounding signal, and sends corresponding precoder information to at least one STA 111, 112, 113 for data transmission;

[0126] 1104: wherein the trigger signal includes a Null Data Packet Announcement (NDPA) signal or a Null Data Packet Request (NDPR) signal, and the detection signal includes a triggered detection Null Data Packet (NDP) signal; wherein the triggered detection NDP signal is based on an Extremely High Throughput (EHT) Trigger Based (TB) Physical Protocol Data Unit (PPDU) frame including a data portion; and wherein the EHT TB PPDU frame sends K spatial streams (SS) 1250 in an EHT Long Training Field (LTF) portion and N SSs 1260 in a data portion, and the EHT TB PPDU frame is configured to allow K to be independent of N.

[0127] This provides a new variant of the TB PPDU with payload.

[0128] As mentioned above, the problem with the TB PPDU (which includes a payload) is that it is currently not possible to send different numbers of SSs in the EHT LTF part and the data part. Here, it is proposed to reuse the TB PPDU main format.

[0129] like Fig.12 As shown, the first option involves a new variant 1200 of the TB PPDU type, in which the number of spatial streams (SS) of the EHT LTF part and the data part is different (K SSs for the EHT LTF part, reference numeral 1250; N SSs for the data part, reference numeral 1260). The number K and the number N can be selected independently. In an example, the data part can be sent with a single SS (N=1) that is replicated for all antennas, and K will depend on the number of Tx antennas indicated by the STA in the capability report. The second option involves a new variant of the TB PPDU type, in which the selected Tx antennas are indicated by the NDPR. The AP can indicate which subset of the Tx antennas should be used for transmission, and the STA will transmit using the indicated subset (in this case, K can be less than or equal to the number of SSs supported for data transmission).

[0130] Fig.13 It is shown (also see Figure 1 and Fig.12) A general method for uplink sounding signal triggering performed by a STA according to a fourth aspect comprises the following steps:

[0131] 1301: stations (STA) 111, 112, 113 receive a trigger signal from an access point (AP) 121;

[0132] 1302: In response to the trigger signal, STAs 111, 112, and 113 send a detection signal to AP 121; and

[0133] 1303: STAs 111, 112, 113 receive, from AP 121, precoder information corresponding to a precoder to be used by STAs 111, 112, 113, determined by AP 121 based on the sounding signal, for data transmission;

[0134] 1304: wherein the trigger signal includes a Null Data Packet Announcement (NDPA) signal or a Null Data Packet Request (NDPR) signal, and the detection signal includes a triggered detection Null Data Packet (NDP) signal; wherein the triggered detection NDP signal is based on an Extremely High Throughput (EHT) Trigger Based (TB) Physical Protocol Data Unit (PPDU) frame including a data portion; and wherein the EHT TB PPDU frame sends K spatial streams (SS) 1250 in an EHT Long Training Field (LTF) portion and N SSs 1260 in a data portion, and the EHT TB PPDU frame is configured to allow K to be independent of N.

[0135] However, this corresponds to the method performed by the STAs 111 , 112 , 113 according to the third aspect.

[0136] like Figure 3A and Figure 3BAs shown and described above, the PPDU type and variant are indicated by the PPDU Type and Compression Mode field 311 in the U-SIG 310. In the present disclosure, several options for indicating new variants are proposed. DL / UL 312b is set to 1, and for all aspects, the same indication can be used for the relevant PPDU type. These options include (i) new values ​​for the PPDU Type and Compression Mode fields - for example, setting the PPDU Type and Compression Mode fields to "2" (or "3"); (ii) U-SIG verification bits - setting the PPDU Type and Compression Mode fields to "0" and setting B2 of U-SIG-2 to "1" - can also be set to "1" in the NDPR; and (iii) special ignore bit combinations - setting the PPDU Type and Compression Mode fields to "0" and using a special combination of 11 ignore bits of the U-SIG for triggered NDP - can be set by the NDPR or TF and copied to the TB U-SIG.

[0137] In order to support accurate UL BF, AP 121 needs to know the number of Tx antennas equipped by STAs 111, 112, and 113. Fig.14 , it is proposed to add a new PHY element 1400 to the capability report.

[0138] If the antenna selection option is used, AP 121 needs to indicate the subset of Tx antennas used for the current sounding transmission. This can be achieved through the following two options. The first option is to indicate the first antenna index and 4 bits for indicating the number of antennas (a total of 8 bits). According to the second option, all Tx antennas can be divided into groups of 2, 4, or 8 antennas, and AP 121 indicates the current group index. 2 bits are required to indicate the group size and 4 bits are required to indicate the group index. For example, if divided into groups of 2 antennas, and when AP 121 wants STA 111, 112, 113 to use antennas 5 and 6 (the 3rd group), "00" can indicate a size of 2, and "0011" can indicate the 3rd group.

[0139] Fig.15 An access point (AP) 1500 according to the fifth aspect is shown. The AP 1500 comprises a processing circuit 1501, which is configured to execute the uplink sounding signal triggering method according to the first aspect or the third aspect.

[0140] Fig.16 A station (STA) 1600 according to the sixth aspect is shown. The STA 1600 comprises a processing circuit 1601, which is configured to execute the uplink sounding signal triggering method according to the second aspect or the fourth aspect.

[0141] The ability to identify STAs 111, 112, 113, 1600 using the power of the estimated channel has been simulated. The main idea is that if the STA 111, 112, 113, 1600 has transmitted a signal, the power of the estimated channel will be high. Otherwise, the power will be low. Therefore, by setting an adjusted threshold, it is possible to identify which STAs 111, 112, 113, 1600 have transmitted a signal and which have not.

[0142] The idea is to compare the power of the estimated channel averaged over all subcarriers with the average RSSI of the received signals (a triggering signal should exceed a threshold).

[0143] Two different scenarios at 20MHz were simulated:

[0144] Case 1: The difference between the two STAs is 6 dB

[0145] Case 2: 2 STAs and the interference signal have the same RSSI, and 1 STA has a 6dB lower RSSI

[0146] Both cases are simulated with CFO uniformly distributed in the range of + / -350Hz, TGn-D channels and actual CHEST. Fig.17 As can be seen in Figure 2, in both cases, the weaker STA has a very good detection rate (100% at -1dB SNR) and no interference false alarms.

[0147] In summary, several benefits / motivations of the present disclosure are as follows:

[0148] Several methods are used to solve the problem of probing NDP with minimal changes to existing PPDU types

[0149] The proposed solution efficiently solves the problems related to the UL BF procedure and enables covering all possible scenarios

[0150] In several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the described embodiments of the device are merely exemplary. For example, the unit division is only a logical function division, and in the actual implementation, it can be other divisions. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not performed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be achieved by using some interfaces. The indirect coupling or communication connection between devices or units can be implemented in electronic, mechanical or other forms.

[0151] The units described as separate components may or may not be physically separated, and the parts shown as units may or may not be physical units, may be located in one location, or may be distributed over multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

[0152] In addition, the functional units in the embodiments disclosed herein may be integrated into one processing unit, or each of the units may exist physically separately, or two or more units may be integrated into one unit.

[0153] abbreviation

[0154] DL: Downlink

[0155] UL: Uplink

[0156] BF: Beamforming

[0157] AP: Access Point

[0158] PHY: Physical layer

[0159] MAC: Media Access Control

[0160] PPDU: PHY Protocol Data Unit

[0161] STA: Station (usually can be AP STA or non-AP STA)

[0162] NDP: Null Data Packet, i.e., a packet containing a preamble (including a Long Training Field (LTF)) and used to estimate the physical channel between the beamformer and the beam receiver so that the precoder can be calculated.

[0163] NDPA: NDP announcement, i.e., a frame sent before NDP, indicating the format of NDP (e.g., how many LTFs), which STAs need to respond, what parameters these STAs should use, etc.

[0164] BFR: Beamforming Report, a frame carrying beamforming / precoding information such as precoding vectors or matrices, SNR corresponding to each precoder, etc.

[0165] BA: Block-ACK: In 802.11, a receiver should generally respond to a data transmission by responding with an ACK; if multiple frames are sent within a single PPDU, each frame must be acknowledged

[0166] TF: Trigger Frame: In 802.11ax, trigger frames are introduced as a means to trigger one or more STAs to transmit simultaneously and in sync with the triggering AP.

[0167] The above-described embodiments are exemplary, and the full disclosure is defined by the claims.

Claims

1. A method triggered by an uplink sounding signal performed by an access point AP, comprising: The AP sends a trigger signal to one or more stations STA, thereby triggering transmission of a corresponding detection signal from at least one STA among the one or more STAs in response to the trigger signal; Receiving, by the AP, the corresponding detection signal from the at least one STA; as well as The AP determines, based on the corresponding sounding signal, a precoder to be used by the at least one STA, and sends corresponding precoder information to the at least one STA for data transmission; Wherein, the trigger signal includes a null data packet announcement NDPA signal or a null data packet request NDPR signal, and the detection signal includes a triggered detection null data packet NDP signal; Wherein, the triggered detection NDP signal is based on a triggered TB physical protocol data unit PPDU frame without a payload or based on an extremely high throughput EHT multi-user MU PPDU frame without a payload; and The U-SIG part of the TB PPDU frame or the EHT MU PPDU frame of the triggered sounding NDP signal includes a parameter indicating the triggered NDP transmission.

2. The method according to claim 1, wherein: The PPDU type TB PPDU or EHT MU PPDU, and / or PPDU variant of the triggered sounding NDP signal is indicated in the PPDU type and compression mode field in the U-SIG part.

3. The method according to claim 2, wherein: The PPDU Type and Compression Mode fields are set to 2 or 3.

4. The method according to claim 2, wherein: The PPDU Type and Compression Mode fields are set to 0, and B2 of U-SIG-2 is set to 1 to indicate a triggered sounding NDP.

5. The method according to claim 2, wherein: The PPDU Type and Compression Mode fields are set to 0, and a combination of 11 ignore bits of the U-SIG is used to indicate a triggered sounding NDP.

6. The method according to claim 1, wherein: The U-SIG portion of the triggered sounding NDP signal includes a UL / DL field set to 1.

7. The method according to claim 1, wherein: The U-SIG portion of the triggered sounding NDP signal includes a spatial reuse field, and the spatial reuse field is reserved or set to not allowed, so that spatial reuse is not allowed when the triggered NDP transmission is indicated.

8. The method according to any one of claims 1 to 7, wherein: The bandwidth BW indicated in the U-SIG portion of the triggered sounding NDP is the same as the BW indicated by the NDPA or NDPR trigger signal.

9. The method according to any one of claims 1 to 8, wherein: The puncturing channel information field of the U-SIG part is reserved.

10. The method according to any one of claims 1 to 9, wherein: The EHT-SIG symbol number indication field of the U-SIG part is reserved.

11. A method for uplink detection signal triggering performed by a station STA, comprising: The STA receives a trigger signal from an access point AP; In response to the trigger signal, sending a detection signal from the STA to the AP; receiving, by the STA from the AP, precoder information corresponding to a precoder to be used by the STA, determined by the AP based on the sounding signal, for data transmission; Wherein, the trigger signal includes a null data packet announcement NDPA signal or a null data packet request NDPR signal, and the detection signal includes a triggered detection null data packet NDP signal; Wherein, the triggered detection NDP signal is based on a triggered TB physical protocol data unit PPDU frame without a payload or based on an extremely high throughput EHT multi-user MU PPDU frame without a payload; and The U-SIG part of the TB PPDU frame or the EHT MU PPDU frame of the triggered sounding NDP signal includes a parameter indicating the triggered NDP transmission.

12. The method according to claim 11, wherein: The PPDU type TB PPDU or EHT MU PPDU, and / or PPDU variant of the triggered sounding NDP signal is indicated in the PPDU type and compression mode field in the U-SIG part.

13. The method according to claim 12, wherein: The PPDU Type and Compression Mode fields are set to 2 or 3.

14. The method according to claim 12, wherein: The PPDU Type and Compression Mode fields are set to 0, and B2 of U-SIG-2 is set to 1 to indicate a triggered sounding NDP.

15. The method according to claim 12, wherein: The PPDU Type and Compression Mode fields are set to 0, and a combination of 11 ignore bits of the U-SIG is used to indicate a triggered sounding NDP.

16. The method according to one of claims 11 to 15, wherein: The U-SIG portion of the triggered sounding NDP signal includes a UL / DL field set to 1.

17. The method according to one of claims 11 to 16, wherein: The U-SIG portion of the triggered sounding NDP signal includes a spatial reuse field, and the spatial reuse field is reserved or set to not allowed, so that spatial reuse is not allowed when the triggered NDP transmission is indicated.

18. The method according to any one of claims 11 to 17, wherein: The bandwidth BW indicated in the U-SIG portion of the triggered sounding NDP is the same as the BW indicated by the NDPA or NDPR trigger signal.

19. The method according to any one of claims 11 to 18, wherein: The puncturing channel information field of the U-SIG part is reserved.

20. The method according to any one of claims 11 to 19, wherein: The EHT-SIG symbol number indication field of the U-SIG part is reserved.

21. A method triggered by an uplink detection signal performed by an access point AP, comprising: The AP sends a trigger signal to one or more stations STA, thereby triggering transmission of a corresponding detection signal from at least one STA among the one or more STAs in response to the trigger signal; Receiving, by the AP, the corresponding detection signal from the at least one STA; as well as The AP determines, based on the corresponding sounding signal, a precoder to be used by the at least one STA, and sends corresponding precoder information to the at least one STA for data transmission; Wherein, the trigger signal includes a null data packet announcement NDPA signal or a null data packet request NDPR signal, and the detection signal includes a triggered detection null data packet NDP signal; Wherein, the triggered detection NDP signal is based on an extremely high throughput EHT triggered TB physical protocol data unit PPDU frame including a data portion; and The EHT TB PPDU frame sends K spatial streams SS in the EHT long training field LTF part and sends N SSs in the data part, and the EHT TB PPDU frame is configured to allow K to be independent of N.

22. The method according to claim 21, wherein: The number K of spatial streams SS in the EHT long training field LTF part depends on the number M of transmit antennas.

23. The method according to claim 21 or 22, wherein: The EHT LTF part includes EHT LTF OFDM symbols, and the number K of EHT LTF OFDM symbols is the number K of transmitting antennas indicated by the at least one STA in the capability report.

24. The method according to any one of claims 21 to 23, wherein: The AP indicates, through the NDPA signal, which subset of transmit antennas the at least one STA will use for transmission.

25. The method according to claim 24, wherein: The triggered sounding NDP is received by the AP from a subset of transmit antennas of the at least one STA.

26. The method according to any one of claims 21 to 25, wherein: The PPDU type EHT MU PPDU and / or PPDU variant of the triggered sounding NDP signal is indicated in the PPDU type and compression mode fields in the U-SIG part.

27. The method according to any one of claims 21 to 26, wherein: The PPDU Type and Compression Mode fields are set to 2 or 3.

28. The method according to any one of claims 21 to 27, wherein: The PPDU Type and Compression Mode fields are set to 0, and B2 of U-SIG-2 is set to 1 to indicate a triggered sounding NDP.

29. The method according to any one of claims 21 to 28, wherein: The PPDU Type and Compression Mode fields are set to 0, and a combination of 11 ignore bits of the U-SIG is used to indicate a triggered sounding NDP.

30. A method for uplink detection signal triggering performed by a station STA, comprising: The station STA receives a trigger signal from an access point AP; In response to the trigger signal, sending a detection signal from the STA to the AP; as well as receiving, by the STA from the AP, precoder information corresponding to a precoder to be used by the STA, determined by the AP based on the sounding signal, for data transmission; Wherein, the trigger signal includes a null data packet announcement NDPA signal or a null data packet request NDPR signal, and the detection signal includes a triggered detection null data packet NDP signal; Wherein, the triggered detection NDP signal is based on an extremely high throughput EHT triggered TB physical protocol data unit PPDU frame including a data portion; and The EHT TB PPDU frame sends K spatial streams SS in the EHT long training field LTF part and sends N SSs in the data part, and the EHT TB PPDU frame is configured to allow K to be independent of N.

31. The method according to claim 30, wherein: The number K of spatial streams SS in the EHT long training field LTF part depends on the number M of transmit antennas.

32. The method according to claim 30 or 31, wherein: The EHT LTF part includes EHT LTF OFDM symbols, and the number K of EHT LTF OFDM symbols is the number K of transmitting antennas indicated by the at least one STA in the capability report.

33. The method according to any one of claims 30 to 32, wherein: The AP indicates, through the NDPA signal, which subset of transmit antennas the at least one STA will use for transmission.

34. The method of claim 33, wherein: The triggered sounding NDP is received by the AP from a subset of transmit antennas of the at least one STA.

35. The method according to any one of claims 30 to 34, wherein: The PPDU type EHT MU PPDU and / or PPDU variant of the triggered sounding NDP signal is indicated in the PPDU type and compression mode fields in the U-SIG part.

36. The method according to any one of claims 30 to 35, wherein: The PPDU Type and Compression Mode fields are set to 2 or 3.

37. A method according to any one of claims 30 to 36, wherein: The PPDU Type and Compression Mode fields are set to 0, and B2 of U-SIG-2 is set to 1 to indicate a triggered sounding NDP.

38. The method according to any one of claims 30 to 37, wherein: The PPDU Type and Compression Mode fields are set to 0, and a combination of 11 ignore bits of the U-SIG is used to indicate a triggered sounding NDP.

39. An access point AP, comprising a processing circuit, wherein the processing circuit is configured to execute the method according to any one of claims 1 to 10 or any one of claims 21 to 29.

40. A station (STA), comprising a processing circuit, the processing circuit being configured to perform the method according to any one of claims 11 to 20 or any one of claims 30 to 38.

41. A computer program comprising instructions which, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 38.

42. A computer readable medium comprising instructions which, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 38.

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