Design of link adaptive training feedback reporting framework

Abstract

A method for providing a link adaptation training (LAT) feedback frame in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and one or more responding STAs. For multi-user (MU) feedback, a LAT feedback report should be triggered by a requesting STA if a previous LAT advertisement frame includes more than one Per-STA Info. For single user (SU) feedback, after the predefined IFS, the LAT feedback frame may be implicitly requested by a previous LAT announcement frame comprising only a single Per-STA Info after which the LAT PPDU follows.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of link adaptation in wireless network communication systems, aiming to improve the speed of the adaptation process. Background Art

[0002] Advanced Wi-Fi standards such as 802.11ax and 802.11be support very high data rates, e.g., 4.8 Gbps to 23 Gbps. Link Adaptation (LA) is a mechanism for adjusting transmission (TX) schemes and parameters, such as the PHY rate specified by the Modulation Coding Scheme (MCS), the number of streams and frequency allocation, Resource Unit (RU) selection, etc. This adjustment process attempts to optimally adapt the parameters to the instantaneous conditions of the wireless link (e.g., channel quality and interference), while meeting other system constraints and requirements.

[0003] One of the most popular implementations is the Minstrel algorithm (https: / / Wireless.wiki.kernel.org / en / developers / documentation / mac80211 / ratecontrol / minstrel). In the Minstrel algorithm, the rate-defining parameters are slowly changed through a "trial and error" process based on the receipt of acknowledgements (ACK) or block acknowledgements (BACK) for the transmitted data packets reported by the receiver (RX). The term "slowly" here means that the algorithm may take a long time to converge to an optimal set of parameters to achieve some predefined metric goals, e.g., packet error rate (PER) = 10%. The optimal here should be understood in the sense of long-term average.

[0004] In addition to BACK / ACK, the specifications of the WLAN IEEE 802.11 standard now also support several types of feedback for assisting LA, such as:

[0005] (i) Signal-to-Noise Ratio (SNR) (Channel Quality Indicator, CQI) of each resource unit (RU): It can indicate that the station (STA) calculates the SNR of a specific RU based on the probe null data packet (NDP) and feeds it back to the requesting access point (AP). However, the problem is whether the AP can trust the calculations performed on the STA side. For example, considering the receiver implementation of a specific STA, there may be questions such as what the relationship is between the SNR and the link performance and how that relationship may affect the calculations.

[0006] (ii) MCS Feedback (MFB): The STA can indicate its preferred MCS. Since the STA's implementation is taken into account, this may be an acceptable metric. However, this method is usually not achievable. In addition, the WLAN specification (WLAN IEEE 802.11) does not enforce / test the accuracy of MFB.

[0007] (iii) A Control High Efficiency Link Adaptation (A-CTRL HLA): The LA control message is included in the frame header as part of any data or management frame sent by a non-AP STA. When indicated as the High-Efficiency (HE) variant by any HE STA, the specific LA control message can be added in the High-Throughput (HT) control section.

[0008] In this context, for a single physical layer rate (PHY rate), there should be a predefined mapping (e.g., a table) of values of the modulation and coding scheme and the number of spatial streams (i.e., MCS and N SS ). This pair can be represented as <MCS,N SS >. Here, <MCS,N SS > can also be called a tuple. Therefore, each PHY rate index value should have at least a single <MCS,N SS > tuple. Then, the link adaptation training (LAT) feedback report should be triggered by the associated / initiating / requesting access point (AP) for multi-user (MU) feedback.

[0009] In view of the above, the design of the Link Adaptation Training Announcement frame needs to consider the following requirements: The non-AP STAs that should measure the LAT PHY Protocol Data Unit (PPDU) should be listed, and the corresponding measurement parameters for each non-AP STA should be listed. Therefore, in response to a LAT Announcement frame followed by a LAT PPDU (both the LAT Announcement frame and the LAT PPDU are sent by the requesting STA), the Link Adaptation Training Feedback Report frame sent back from the expected receiving non-AP STA needs to list the <MCS,N SS > tuple and RU that the LAT feedback report refers to, and include in the feedback report a link performance metric that corresponds to each entry in the list measured by the non-AP STA that sends the LAT feedback report.

[0010] In addition, the Link Adaptation Training Feedback Report Polling Trigger Frame (Trigger Frame, TF) needs to be adjusted so that it can trigger Link Adaptation Training Feedback Reports from more than one non-AP STA. SUMMARY OF THE INVENTION

[0011] In view of the above, the present disclosure relates to methods and apparatuses for communication in the field of fast link adaptation in a wireless network communication system.

[0012] The present disclosure is defined by the scope of the independent claims. The dependent claims provide advantageous embodiments of the present disclosure.

[0013] According to a first aspect, a method for providing link adaptation training (LAT) feedback frames in a wireless local access network (WLAN) is provided, where the WLAN includes a requesting station and one or more responding STAs, and the method includes: the one or more responding STAs send LAT feedback frames to the requesting STA, where the sending starts after a predefined inter frame space (IFS) after each of the responding STAs in the responding STAs receives a dedicated trigger frame (TF) for the corresponding responding STA from the requesting STA; the TF follows a link adaptation training physical layer protocol data unit (LAT-PPDU); before the LAT-PPDU is a LAT announcement frame determined by the corresponding responding STA to include per station information (Per-STA Info) for the corresponding responding STA; where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0014] According to a second aspect, a method for providing link adaptation training (LAT) feedback frames in a wireless local access network (WLAN) is provided. The WLAN includes a requesting station (STA) and a responding STA. The method includes: the responding STA sending an LAT feedback frame to the requesting STA, where the sending starts after a predefined inter frame space (IFS) after the responding STA finishes receiving a link adaptation training physical layer protocol data unit (LAT-PPDU), and the LAT-PPDU is received after the responding STA determines that a previous LAT announcement frame includes only a single per station information (Per-STA Info) for the responding STA; the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0015] Therefore, according to the first aspect, for multi user (MU) feedback, if a previous LAT announcement frame includes more than one Per-STA Info, the LAT feedback report should be triggered by the requesting STA. According to the second aspect, for single user (SU) feedback, after a predefined IFS, the LAT feedback frame can be implicitly requested by a previous LAT announcement frame that includes only a single Per-STA Info, followed by an LAT PPDU. For SU feedback, a trigger frame (TF) can be included, but it is not necessarily required for the SU feedback case.

[0016] Therefore, an LAT feedback frame is created that carries several different measured link performance metrics. This can provide a reliable estimate of the expected performance of several combinations of MCS, N SS and RU to the requesting / sending side in a relatively short time. The requesting side will use different MCS values and N in some (e.g., single or multiple) RUs SSThe value sends a LAT PPDU containing a set of predefined (i.e., known) codewords to the receiving side. The receiving side responds with the measured BER or the number of error bits per codeword as feedback. Here, when considering a larger error rate and rounding up, we can use at most 1 byte to represent the number of error bits in a codeword. If necessary, the requesting side can "convert" the reported BER metric to a PER metric. This enables the requesting side to quickly gather some insights into the expected performance, so the requesting side can use RU-MCS-N SS combination, which meets some predefined criteria when sent to each receiving side. Therefore, this method can be used to significantly shorten the convergence time of the (data-only) ACK / BACK "outer loop" LA mechanism (such as Minstrel); in other words, this method does not necessarily replace link adaptation mechanisms such as Minstrel, but helps these mechanisms converge faster.

[0017] In a possible first implementation of the method according to the first aspect, or in a possible first implementation of the method according to the second aspect, the frame body of the LAT feedback frame further includes: a LAT feedback control field including a set of parameters, the set of parameters being related to the measurement on which the LAT feedback from the responding STA is based; a field including a set of per-resource unit (RU) feedback result information (i.e., Per-RU Feedback Results Info set), the Per-RU Feedback Results Info set including link performance metrics (i.e., Measured Metrics) measured by the responding STA.

[0018] In this description, the Bit Error Rate (BER) is an example of a link performance metric. Other examples of link performance metrics can include the (absolute) number of error bits that may be quantified according to some granularity, or the SNR value measured in dB.

[0019] In any of the above implementations of the method according to the first aspect, in a possible second implementation of the method, or in any of the above implementations of the method according to the second aspect, in a possible second implementation of the method, the LAT feedback control field at least includes the following sub-fields: a sub-field indicating the index of the codeword (i.e., Codeword Index), where the codeword index indicates the codeword used for LAT; a sub-field indicating the size of the RU corresponding to the measurement metric included in each Per-RU feedback result information field; a sub-field including a bitmap indicating which RUs the responding STA has measured; a sub-field including a bitmap indicating which metrics the responding STA has measured and fed back.

[0020] In a first or second implementation of the method according to the first aspect, in a possible third implementation of the method, or in a first or second implementation of the method according to the second aspect, in a possible third implementation of the method, the Per-RU feedback result information set at least includes the following fields: a sub-field indicating the element ID; a sub-field indicating the element ID extension; a sub-field indicating the Length; one or more Per-RU feedback result information fields.

[0021] In a third implementation of the method according to the first aspect, in a possible fourth implementation of the method, or in a third implementation of the method according to the second aspect, in a possible fourth implementation of the method, the number of information fields included in the set of Per-RU feedback result information fields at least depends on: the bandwidth of the channel (i.e., Channel Bandwidth); the size of the RU corresponding to the measurement metric; a bitmap indicating which RUs the responding STA has measured; where the valid RU index is set to 1, indicating the RU corresponding to the measurement metric.

[0022] In a third or fourth implementation of the method according to the first aspect, in a possible fifth implementation of the method, or in a third or fourth implementation of the method according to the second aspect, in a possible fifth implementation of the method, each Per-RU feedback result information field in the Per-RU feedback result information field at least includes the following sub-fields: a sub-field indicating the index of the RU (i.e., RU index); a sub-field indicating the set of PHY rates obtained after measuring each reported metric; a sub-field containing the number M, where the number M indicates the number of PHY rates included in the set of PHY rate indices, and M is an integer in the range from 0 to 15; a sub-field containing k sets of measurement metrics, where k is an integer greater than 0.

[0023] In a fifth implementation of the method according to the first aspect, in a possible sixth implementation of the method, or in a fifth implementation of the method according to the second aspect, in a possible sixth implementation of the method, for a set of measurement metrics x (where x = 1, 2,..., k), the measured value of metric x is provided according to each PHY rate indicated in the set of PHY rate indices, where the size of the subfield representing each metric value depends on the measurement metric type and is indicated as a non-zero value in the LAT feedback control field or in the measurement metric information bitmap subfield, where: value 01 indicates that the size of the metric value is represented by one byte; value 10 indicates that the size of the metric value is represented by two bytes.

[0024] In a fifth or sixth implementation of the method according to the first aspect, in a possible seventh implementation of the method, or in a fifth or sixth implementation of the method according to the second aspect, in a possible seventh implementation of the method, the number of error bits of each codeword is used as a measurement metric, where the valid value of the measurement metric is an integer in the range 0 to 254, where values 0 to 253 correspondingly indicate the number of error bits, and value 254 indicates at least 254 error bits.

[0025] In any one of the fifth to seventh implementations of the method according to the first aspect, in a possible eighth implementation of the method, or in any one of the fifth to seventh implementations of the method according to the second aspect, in a possible eighth implementation of the method, the invalid value corresponding to each measurement metric is indicated by the following values: value 255 if the metric value is represented by a one-byte subfield; value 65535 if the metric value is represented by a two-byte subfield.

[0026] The present disclosure also provides a third aspect, namely, a method for providing link adaptation training (LAT) feedback frames in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and one or more responding STAs, and the method includes: sending an LAT announcement frame from the requesting STA to the one or more responding STAs, where a link adaptation physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; sending a dedicated trigger frame (TF) from the requesting STA to the one or more responding STAs, where the dedicated TF triggers the sending of an LAT feedback frame after a predefined inter frame space (IFS), and the LAT feedback frame is sent by the one or more responding STAs provided that the one or more responding STAs have been included in each station information (Per-STAInfo) for the corresponding responding STA in the LAT announcement frame; the requesting STA receiving the LAT feedback frame from the one or more responding STAs; where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0027] The present disclosure also provides a fourth aspect, namely, a method for providing link adaptation training (LAT) feedback frames in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and a responding STA, and the method includes: sending an LAT announcement frame from the requesting STA to the responding STA, where a link adaptation training physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; the requesting STA receiving an LAT feedback frame, where after determining that a previously received LAT announcement frame by the responding STA includes only a single per station information (Per-STAInfo) for the responding STA and is followed by a link adaptation training physical layer protocol data unit (LAT-PPDU), after a predefined inter frame space (IFS), the LAT feedback frame is sent from the responding STA; where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, where the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0028] The present disclosure also provides a fifth aspect, namely, a device in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and one or more responding STAs. Among them, the one or more responding STAs are configured to: send a LAT feedback frame from the one or more responding STAs to the requesting STA, where the sending starts after a predefined inter-frame space (IFS) after each of the responding STAs in the responding STAs receives a dedicated trigger frame (TF) for the corresponding responding STA from the requesting STA; the TF follows a link adaptation training physical layer protocol data unit (LAT-PPDU); before the LAT-PPDU is a LAT announcement frame, which is determined by the corresponding responding STA to include per station information (Per-STA Info) for the corresponding responding STA, where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, where the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0029] The present disclosure also provides a sixth aspect, namely, a device in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and a responding STA. Among them, the responding STA is configured to: The responding STA sends a LAT feedback frame to the requesting STA, where the sending starts after the responding STA completes receiving a link adaptation training physical layer protocol data unit (LAT-PPDU) and after a predefined inter frame space (IFS). The LAT-PPDU is received after the responding STA determines that a previous LAT announcement frame only includes a single per station information (Per-STA Info) for the responding STA. The LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, where the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0030] In a possible first implementation manner of the device according to the fifth aspect, or in a possible first implementation manner of the device according to the sixth aspect, the frame body of the LAT feedback frame further includes: a LAT feedback control field including a set of parameters, where the set of parameters is related to the measurement based on which the LAT feedback from the responding STA is made; a field including a set of per resource unit (RU) feedback result information (i.e., a Per-RU Feedback Results Info set), and the Per-RU Feedback Results Info set includes link performance metrics measured by the responding STA (i.e., Measured Metrics).

[0031] In any of the above implementations of the apparatus according to the fifth aspect, in a possible second implementation of the apparatus, or in any of the above implementations of the apparatus according to the sixth aspect, in a possible second implementation of the apparatus, the LAT feedback control field at least includes the following sub-fields: a sub-field indicating the index of the codeword (i.e., Codeword Index), where the codeword index indicates the codeword used for LAT; a sub-field indicating the size of the RU corresponding to the measurement metric included in each Per-RU feedback result information field; a sub-field including a bitmap indicating which RUs the responding STA has measured; a sub-field including a bitmap indicating which metrics the responding STA has fed back.

[0032] In a first or second implementation of the apparatus according to the fifth aspect, in a possible third implementation of the apparatus, or in a first or second implementation of the apparatus according to the sixth aspect, in a possible third implementation of the apparatus, the Per-RU feedback result information set at least includes the following fields: a sub-field indicating the element ID; a sub-field indicating the element ID extension; a sub-field indicating the Length; one or more Per-RU feedback result information fields.

[0033] In a third implementation of the apparatus according to the fifth aspect, in a possible fourth implementation of the apparatus, or in a third implementation of the apparatus according to the sixth aspect, in a possible fourth implementation of the apparatus, the number of information fields included in the set of Per-RU feedback result information fields depends at least on: the bandwidth of the channel (i.e., Channel Bandwidth); the size of the RU corresponding to the measurement metric; a bitmap indicating which RUs the responding STA has measured; where the valid RU index is set to 1, indicating the RU corresponding to the measurement metric.

[0034] In a third or fourth implementation of the apparatus according to the fifth aspect, in a possible fifth implementation of the apparatus, or in a third or fourth implementation of the apparatus according to the sixth aspect, in a possible fifth implementation of the apparatus, each Per-RU feedback result information field in the Per-RU feedback result information field at least includes the following sub-fields: a sub-field indicating the index of the RU (i.e., RU index); a sub-field indicating the set of PHY rates obtained after measuring each reported metric; a sub-field containing the number M, where the number M indicates the number of PHY rates included in the set of PHY rate indices, where M is an integer in the range 0 to 15; a sub-field containing k sets of measurement metrics, where k is an integer greater than 0.

[0035] In a fifth implementation of the apparatus according to the fifth aspect, in a possible sixth implementation of the apparatus, or in a fifth implementation of the apparatus according to the sixth aspect, in a possible sixth implementation of the apparatus, for a set of measurement metrics x (where x = 1, 2, …, k), the measured value of metric x is provided according to each PHY rate indicated in the set of PHY rate indices, where the size of the subfield representing each metric value depends on the measurement metric type and is indicated as a non-zero value in the LAT feedback control field or in the measurement metric information bitmap subfield, where: value 01 indicates that the size of the metric value is represented by one byte; value 10 indicates that the size of the metric value is represented by two bytes.

[0036] In a fifth or sixth implementation of the apparatus according to the fifth aspect, in a possible seventh implementation of the apparatus, or in a fifth or sixth implementation of the apparatus according to the sixth aspect, in a possible seventh implementation of the apparatus, the number of error bits of each codeword is used as a measurement metric, where the valid value of the measurement metric is an integer within the range of 0 to 254, where values 0 to 253 indicate the number of error bits accordingly, and value 254 indicates at least 254 error bits.

[0037] In any one of the fifth to seventh implementations of the apparatus according to the fifth aspect, in a possible eighth implementation of the apparatus, or in any one of the fifth to seventh implementations of the apparatus according to the sixth aspect, in a possible eighth implementation of the apparatus, the invalid value corresponding to each measurement metric is indicated by the following values: value 255 if the metric value is represented by a one-byte subfield; value 65535 if the metric value is represented by a two-byte subfield.

[0038] The present disclosure also provides a seventh aspect, namely, a device in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and one or more responding STAs. Among them, the requesting STA is used to: send a LAT announcement frame from the requesting STA to the one or more responding STAs, where a link adaptation physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; send a dedicated trigger frame (TF) from the requesting STA to the one or more responding STAs, where the dedicated TF triggers the sending of a LAT feedback frame after a predefined inter frame space (IFS), and the LAT feedback frame is sent by the one or more responding STAs provided that the one or more responding STAs have been included in the per station information (Per-STA Info) for the corresponding responding STA in the LAT announcement frame; receive the LAT feedback frame from the one or more responding STAs, where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0039] The present disclosure also provides an eighth aspect, namely, a device in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and a responding STA. Among them, the requesting STA is used for: sending a LAT announcement frame from the requesting STA to the responding STA, where a link adaptation training physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; the requesting STA receives a LAT feedback frame, where after determining that the previously received LAT announcement frame by the responding STA only includes a single per station information (Per-STA Info) for the responding STA and is followed by a link adaptation training physical layer protocol data unit (LAT-PPDU), after a predefined inter frame space (IFS), the LAT feedback frame is sent from the responding STA, where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, where the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0040] The present disclosure also provides a ninth aspect, namely, a computer program product including program code, which is used to execute the method according to any implementation manner of the method according to the first aspect or the method according to the first aspect; or the method according to any implementation manner of the method according to the second aspect or the method according to the second aspect; or the method according to the third aspect; or the method according to the fourth aspect when the program code is executed on a computer or a processor.

[0041] The present disclosure also provides a tenth aspect, namely, a non-transitory computer-readable medium carrying program code, which causes the computer device to execute the method according to any implementation manner of the method according to the first aspect or the method according to the first aspect; or the method according to any implementation manner of the method according to the second aspect or the method according to the second aspect; or the method according to the third aspect; or the method according to the fourth aspect when the program code is executed by the computer device.

[0042] The present disclosure also provides an eleventh aspect, namely, a device in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and one or more responding STAs each including a sending unit. Among them, the sending unit is configured to: send a LAT feedback frame from the one or more responding STAs to the requesting STA, where the sending starts after a predefined inter-frame space (IFS) after each of the responding STAs in the responding STAs receives a dedicated trigger frame (TF) for the corresponding responding STA from the requesting STA; the TF follows a link adaptation training physical layer protocol data unit (LAT-PPDU); before the LAT-PPDU is a LAT announcement frame, which is determined by the corresponding responding STA to include per station information (Per-STA Info) for the corresponding responding STA; where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, where the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0043] The present disclosure also provides a twelfth aspect, namely, a device in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and one or more responding STAs each including a sending unit. Among them, the sending unit is configured to: the responding STA sends a LAT feedback frame to the requesting STA, where the sending starts after the responding STA completes receiving a link adaptation training physical layer protocol data unit (LAT-PPDU) and after a predefined inter frame space (IFS), and the LAT-PPDU is received after the responding STA determines that a previous LAT announcement frame includes only a single per station information (Per-STA Info) for the responding STA; the LAT feedback frame is a management frame of the "Action NoAck" subtype; the LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0044] The present disclosure also provides a thirteenth aspect, namely, a device in a wireless local access network (WLAN), where the WLAN includes a requesting station (STA) and one or more responding STAs. Among them, the requesting STA includes a sending unit and a receiving unit. The sending unit is configured to: send a LAT announcement frame from the requesting STA to the one or more responding STAs, where a link adaptation physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; send a dedicated trigger frame (TF) from the requesting STA to the one or more responding STAs, where the dedicated TF triggers the sending of a LAT feedback frame after a predefined inter frame space (IFS), and the LAT feedback frame is sent by the one or more responding STAs provided that the one or more responding STAs have been included in each station information (Per-STAInfo) for the corresponding responding STA in the LAT announcement frame; The receiving unit is configured to: receive the LAT feedback frame from the one or more responding STAs; where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0045] The present disclosure also provides a fourteenth aspect, namely, a device in a wireless local access network (WLAN), where the WLAN includes a station (STA) and a responding STA. Among them, the requesting STA includes a sending unit and a receiving unit. Among them, the sending unit is configured to: send a LAT advertisement frame from the requesting STA to the responding STA, where a link adaptation training physical layer protocol data unit (LAT-PPDU) follows the LAT advertisement frame; the receiving unit is configured to: receive a LAT feedback frame, where after determining that the previously received LAT advertisement frame by the responding STA only includes a single per station information (Per-STA Info) for the responding STA and is followed by a link adaptation training physical layer protocol data unit (LAT-PPDU), after a predefined inter frame space (IFS), the LAT feedback frame is sent from the responding STA; where the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, where the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0046] Any of the above devices may also be referred to as a device. Any of the above devices may be embodied on an integrated chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the drawings:

[0048] Figure 1 An example of an infrastructure BSS in a wireless communication system is schematically shown.

[0049] Figure 2 Shows the possible combinations of MCS values and N SS values and a predefined table of their associated PHY rate indices according to another embodiment of the present disclosure.

[0050] Figure 3Shows the relationship between the Signal to Noise Ratio (SNR) (unit: dB) and the Packet Error Rate (PER).

[0051] Figure 4 Shows a method for providing link adaptation training (LAT) feedback frames for multi-user operation mode or single-user operation mode (i.e., abbreviated as MU mode or SU mode respectively) in a wireless local access network according to the first embodiment of the present disclosure.

[0052] Figure 5 Shows a method for providing link adaptation training (LAT) feedback frames for the SU mode in a wireless local access network according to the first embodiment of the present disclosure.

[0053] Figure 6 Shows the structure of the LAT feedback frame and the LAT feedback frame according to the first embodiment of the present disclosure.

[0054] Figure 7 Shows the structure of the LAT feedback control field according to the second embodiment of the present disclosure.

[0055] Figure 8 Shows the structure of the field indicating the set of Per-RU feedback result information according to the third embodiment of the present disclosure.

[0056] Figure 9 Shows regarding Figure 6 Another embodiment of the present disclosure about the detailed information of the RU bitmap indication subfield.

[0057] Figure 10 Shows according to Figure 8 The detailed information.

[0058] Figure 11 Shows regarding Figure 6 Another embodiment of the present disclosure about the detailed information of the RU bitmap indication subfield.

[0059] Figure 12 Shows according to Figure 11 The detailed information.

[0060] Figure 13 Shows the further detailed information of the Per-RU feedback result information field according to the fifth embodiment of the present disclosure.

[0061] Figure 14 Shows an example of a single set of measured link performance metrics of the Per-RU feedback result information field according to the sixth embodiment of the present disclosure.

[0062] Figure 15 Another embodiment of the present disclosure is shown for further providing link adaptation training (LAT) feedback frames for the MU mode in a wireless local access network.

[0063] Figure 16 Another embodiment of the present disclosure is shown for providing link adaptation training (LAT) feedback frames for the SU mode in a wireless local access network. Figure 15 of the present disclosure.

[0064] Figure 17 Another embodiment of the present disclosure is shown for providing an apparatus in a wireless local access network (WLAN) for the MU mode.

[0065] Figure 18 Another embodiment of the present disclosure is shown for providing an apparatus in a wireless communication network (WLAN) for the SU mode. Figure 17 of the present disclosure.

[0066] Figure 19 Another embodiment of the present disclosure is shown for providing an apparatus in a wireless local access network (WLAN) for the MU mode.

[0067] Figure 20 Another embodiment of the present disclosure is shown for providing an apparatus in a wireless communication network (WLAN) for the SU mode. Figure 19 of the present disclosure. Detailed Description

[0068] In the following description, reference is made to the accompanying drawings which form a part hereof, and which show, by way of illustration, specific aspects of embodiments of the present disclosure or specific aspects in which embodiments of the present disclosure may be used. It should be understood that embodiments of the present disclosure may be used in other aspects and include structural or logical changes not depicted in the drawings. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0069] For example, it should be understood that the disclosure related to the described method may equally apply to the corresponding device or system for performing 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 (e.g., functional units) to perform the one or more described method steps (e.g., one unit performs one or more steps, or multiple units respectively perform one or more of the multiple 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 apparatus is described based on one or more units (e.g., functional units), the corresponding method may include a step to perform the functions of the one or more units (e.g., one step performs the functions of one or more units, or multiple steps respectively perform the functions of one or more of the multiple units), even if the one or more steps are not explicitly described or shown in the drawings. Additionally, it should be understood that, unless otherwise stated, the features of the various exemplary embodiments and / or aspects described herein may be combined with each other.

[0070] Figure 1FIG. 0 shows an example of a wireless communication system 100. The communication system 100 includes an access point (AP) 105 that serves one or more stations (STAs) 110, 112, 114, 116, and 118. The AP 105 generally controls aspects of communication with its associated stations, such as radio frequency channels, transmission power limits, authentication, and security. In some cases, in the communication system 100, a transmitter can access wireless resources for uplink transmission (i.e., the link from the STA to the AP) and downlink transmission (i.e., the link from the AP to the STA) based on a distributed contention mechanism commonly referred to as carrier sensing multiple access with collision avoidance (CSMA / CA). In some examples, the AP is referred to as a NodeB, evolved NodeB (eNB), next generation (NG) NodeB (gNB), master eNB (MeNB), secondary eNB (SeNB), master gNB (MgNB), secondary gNB (SgNB), network controller, control node, base station, access node, transmission point (TP), transmission-reception point (TRP), cell, carrier, macro cell, femto cell, pico cell, etc., while the STA can generally also be referred to as a user equipment (UE), mobile station, mobile unit, terminal, user, subscriber, station, etc. The AP can provide wireless access according to one or more wireless communication protocols, such as Wi-Fi 802.11a / b / g / n / ac / ad / ax / ay / be, Third Generation Partnership Project (3GPP) long term evolution (LTE), LTE advanced (LTE-A), 5G, 5G LTE, 5G NR, High Speed Packet Access (HSPA), etc. It should be understood that although the communication system can employ multiple APs capable of communicating with multiple stations, for simplicity, Figure 1 only one AP 105 and five stations 110 to 118 are shown in FIG.

[0071] In IEEE 802.11, data payloads are encoded in the physical (PHY) layer to provide efficient transmission, error detection capabilities, error correction capabilities, or a combination thereof. In an IEEE 802.11-compliant wireless network, data payloads can be encoded using binary convolutional coding (BCC) or low-density parity check (LDPC) coding. In the case of BCC coding, the entire information bit stream is sequentially fed into a generator that generates the coded bits. Each successive subset of coded bits is a function of the information bits currently in the generator's buffer, and the size of this subset is typically 6 bits. In the case of LDPC coding, several codeword sizes are defined. The information bits are divided into separate, non-overlapping parts. These parts are encoded separately. To align with a predefined LDPC codeword size, the information bits can be padded with so-called shortening bits, and to match the desired coding rate, the output can be punctured or repeated.

[0072] As described above, for a single physical layer rate (PHY rate), there should be a predefined mapping (e.g., a table) of pairs of values of modulation coding schemes and the number of spatial streams, i.e., MCS and N SS . This pair can be represented as <MCS,N SS >. Here, <MCS,N SS > can also be referred to as a tuple. Thus, each <MCS,N SS > tuple is represented by a single value indexed by the PHY rate. Then, a link adaptation training (LAT) feedback report should be triggered by the associated access point (AP) for multi-user (MU) feedback transmission. If a previous LAT announcement frame includes more than a single per station (Per-STA) information, MU feedback is defined here. A single user (SU) feedback report can be triggered using a trigger frame (TF).

[0073] More specifically, when sending training data to a responder, the responder should be indicated which codewords (CWs) are to be sent within the training data packet (i.e., PPDU) and their corresponding MCS and N SS (i.e., the pair or tuple). Thus, the training data packet should include overhead. In this way, an indicator of the corresponding positions of the CWs and their corresponding MCS and N SS can also be sent. For the overhead, there are several options to choose from:

[0074] Option 1: According to the first option, the overhead can include using a predetermined number of bits to explicitly indicate each MCS value and the N SS value. This can be done through the extremely high throughput signal field EHT-SIG / LA-SIG. Specifically, 4 bits can be used to indicate each MCS value, and 2 or 3 bits can be used to indicate the number of spatial streams N SS . It should be understood that different numbers of bits can also be used.

[0075] Option 2: According to the second option, the overhead can indicate each combination of MCS and N to be used by indicating the corresponding entry in a predefined table. SS The predefined table can list some or all of the PHY rate indices, where each PHY rate index is associated with a unique pair of MCS values and N SS values in a predefined manner. Specifically, the table can arrange all combinations of MCS and N SS in ascending order of PHY throughput. For example, 16 * 8 = 128 combinations are required, and each combination in the list can be indicated. For example, 7 bits are used for each index.

[0076] For example, Figure 2 the second option is illustrated by showing 10 combinations out of 128 possible combinations of MCS and N SS combinations. More specifically, Figure 2 a table including ten columns with indices 0, 1,..., 9 is shown, where the possible combinations of MCS and N SS are listed, and the number of bits per subcarrier for each of the 10 combinations is indicated. Figure 2 The MCS values in the table follow the convention of the IEEE802.11 WLAN standard, and each value indicates a specific modulation type and coding rate.

[0077] Option 3: According to the third option, the table described for the second option can be further shortened to only include Figure 2 a subset of the combinations shown, while omitting the impractical combinations in the table. For example, MCS 0 with N SS = 2. Therefore, the table may be much shorter than the table of option 2; for example, the table can include only 32 combinations instead of 128 combinations.

[0078] Option 4: According to the fourth option, for a single value of N SS , the overhead can include an indication of the value of MCS used and the order of the values of MCS used. In other words, according to this option, for a single value of N SS , the overhead can include an index referring to one of the options in a predefined option list that indicates the value of MCS and the order of MCS.

[0079] Option 5: According to the fifth option, the overhead can include an index pointing to a specific entry in a predefined table, where the predefined table uses a field with a predefined number of bits to indicate the order of modulation codewords having corresponding MCS and N SS combinations. In other words, the overhead can include an indicator of an entry in a predefined table that specifies the order of CWs having MCS and N SS combinations.

[0080] In the present disclosure, in order to minimize the LA convergence time as much as possible, the initiating station needs to make a reliable estimate of the expected performance as quickly as possible, at least for several combinations of MCS and RU. Attention should be focused on the coded bit error rate (BER), which is reported as a link performance metric, as Figure 5 shown.

[0081] Figure 3 shows the relationship between the signal-to-noise ratio (SNR) (unit: dB) and the packet error rate (PER). Figure 3 shows four tuples of MCS and N SS , i.e., <MCS, N SS > are <0,1>, <7,1>, <4,2>, and <2,1>. For each of these tuples, the PER is shown, and the corresponding BER is also shown.

[0082] Considering that the actual operating PER is below 20% to 30%, the corresponding BER is in the range of 2% to 3%. The maximum number of information bits in a codeword is 1620, corresponding to a coding rate of 5 / 6, and 2% to 3% of which results in approximately 30 to 50 error bits.

[0083] Therefore, for the following cases, attention should be focused on the BER, which is reported as a link performance metric.

[0084] Example 1

[0085] Figure 4 shows the first embodiment of the present disclosure. Figure 4 shows a method for providing link adaptation training (LAT) feedback frames in a wireless local access network. According to Figure 4, the wireless local access network includes a requesting station (STA) and one or more responding STAs. The method includes step 251: one or more responding STAs send a LAT feedback frame to the requesting STA, where the sending starts after a predefined inter frame space (IFS) after each of the responding STAs in the responding STAs receives a dedicated trigger frame (TF) for the corresponding responding STA from the requesting STA; the TF follows a link adaptation training physical layer protocol data unit (LAT-PPDU); before the LAT-PPDU is a LAT announcement frame, which is determined by the corresponding responding STA to include per station information (Per-STA Info) for the corresponding responding STA. Here, the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, where the frame body includes: a field indicating the action category; a field indicating the action category value corresponding to the action category.

[0086] Here, it should be noted that the dedicated trigger frame follows after a predefined inter frame space (IFS) after receiving the previous LAT announcement frame, and the link adaptation training physical layer protocol data unit (LAT-PPDU) follows after the previous LAT announcement frame. Otherwise, since there are no valid LAT measurement values to send, the STA will not send any LAT feedback frames.

[0087] Similarly, Figure 5A method for providing link adaptation training (LAT) feedback frames in a wireless local access network (WLAN) is shown. The WLAN includes a requesting station (STA) and a responding STA. The method includes step 351: The responding STA sends an LAT feedback frame to the requesting STA. The sending starts after the responding STA finishes receiving a link adaptation training physical layer protocol data unit (LAT-PPDU) and after a predefined inter frame space (IFS). The LAT-PPDU is received after the responding STA determines that a previous LAT announcement frame includes only a single per station information (Per-STA Info) for the responding STA. Here, the LAT feedback frame is a management frame of the "Action NoAck" subtype; the LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0088] Here, the dedicated trigger frame (TF) should be understood as the TF defined for the LAT feedback report. The dedicated TF may include an indication of a subset of the expected receiving STA / responding STA, and the expected receiving STA / responding STA includes only non-access point stations (non-AP STAs), and the non-AP STAs are included in the N per station information (Per-STA Info) fields of the LAT announcement frame, where N is an integer greater than 0.

[0089] For example, the dedicated TF sent can be designated as a LAT feedback report poll. For the case of LAT feedback report poll, the TF only includes a subset of non-AP STAs included in the Per-STA Info of the previous LAT announcement frame. In a method for polling link adaption training (LAT) feedback reports in a wireless communication network (WLAN), the wireless communication network includes a requesting STA and one or more expected receiving STAs. This specifically relates to the case of multi-link operation (MLO). For multi-link operation (MLO), the receiving STA belongs to a multi-link device (MLD). Here, the LAT feedback report trigger frame (TF) polls the following LAT feedback report. The feedback report is measured on the same link as the LAT feedback report poll TF is sent on; and / or the feedback report is measured on other links except the link on which the LAT feedback report poll TF is sent, where the feedback report is measured by a non-AP STA belonging to the same MLD. For example, the LAT report poll TF can be sent through a 6 GHz link. Then, the LAT report poll TF includes a request for the most recent measurements made on the 6 GHz link and the 5 GHz link, that is, from non-AP STAs belonging to the same non-AP MLD. In addition, the LAT feedback report TF can include a trigger-related part and an indication is added in the trigger-related part. The trigger-related part can at least include: a part including link information; and / or a part including a conversation token that indicates the report of the specific measurement.

[0090] Figure 6 shows the structure of the LAT feedback frame 201 and the LAT feedback frame according to the first embodiment of the present disclosure. In Figure 6 it, the LAT feedback frame 201 is a management frame, that is, the frame type of the LAT feedback frame 201 is of the management type. The structure of the LAT feedback frame 201 includes a management header field (i.e., MAC header 210), a field including a frame body (i.e., frame body 212), and a frame check sequence (FCS) 214.

[0091] As Figure 6 shown, the frame body 212 includes a set of sub-fields 301. As Figure 6As shown, sub-field 310 indicates a new action category (Action Category), and correspondingly, sub-field 312 indicates the value of the action category (Action Category value). Here, for example, sub-fields 310 and 312 can be filled with the action category: Link Adaptation Training (LAT), and the action category value: Link Adaptation Training Feedback. Here, using the management unacknowledged action frame can dynamically include various elements for future expansion while keeping the length of the entire frame (in bytes) at the required minimum length.

[0092] Figure 6 The set 301 of sub-fields also includes a sub-field 314 (i.e., the LAT feedback control field) indicating the control of the LAT feedback. The LAT feedback control field can include a set of parameters based on which the LAT report is measured. In addition, Figure 6 The set 301 of sub-fields of includes a sub-field 316 (i.e., the Per-RU feedback result information set) indicating a set of feedback result information for each RU. The set of sub-fields 316 includes a set of Per-RU feedback result information, and each Per-RU feedback result information is related to a specific RU for which the non-AP STA measures the received codeword. Here, the Per-RU feedback result information includes the measurement metric values for each subset of the <MCS, N SS > tuple that the non-AP STA is requested to measure for each specific RU.

[0093] Embodiment 2

[0094] Figure 7 Also shown is the structure of the LAT feedback control field according to the second embodiment of the present disclosure. Figure 7 Shown is Figure 6 the set 301 of sub-fields. The elements of the set 301 of sub-fields are the same as the elements shown in Figure 6 For specific descriptions, refer to Figure 6 .

[0095] Figure 7 Also shown is that the LAT feedback control field 314 can include a subset 401 of sub-fields. Figure 7 The subset 401 of sub-fields of can at least include the following sub-fields:

[0096] Subfield 412 that indicates the index of the indication codeword (i.e., Codeword Index). This refers to the codeword to be used for training. That is, this codeword is to be used in the subsequent LAT Physical Layer Protocol Data Unit (PPDU) after the LAT announcement frame following a predefined Inter-Frame Space (IFS).

[0097] Here, in the case where a single codeword is being used by the requesting side (i.e., the initiating station) in the LAT PPDU, for example, when the codeword is predefined in some standard specifications or has been indicated earlier to all STAs involved in this process, the codeword index subfield 412 can be omitted from the LAT feedback control field 314.

[0098] Figure 7 The subset 401 of the subfields of the LAT feedback control field 314 shown also includes a subfield 416 that indicates the coding granularity of the RU (i.e., RU granularity). The granularity can also be understood as the size of the resource unit (RU) corresponding to the metric used for measurement. For example, the granularity (i.e., RU granularity) can be one of the following: 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 320 MHz.

[0099] Figure 7 The subset 401 of the subfields of the LAT feedback control field 314 shown may also include a subfield 418 (i.e., RU Bitmap indication), which includes a bitmap indicating which RUs should be measured.

[0100] In addition, Figure 7 The subset 401 of the subfields of the LAT feedback control field 314 shown also includes a subfield 420 that indicates the bitmap of the measured metrics (i.e., Measured Metrics Info bitmap). The Measured Metrics Info bitmap 420 can be represented as a bitmap with 16 bits. The Measured Metrics Info bitmap 420 indicates which link performance metrics have been measured and fed back. It should be noted that in the case where a single performance metric is being used, for example, using a predefined metric according to some standard specifications or a metric indicated earlier to the STAs involved in this process, the Measured Metrics Info bitmap subfield 420 can be omitted from the subset 401 of the subfields of the LAT feedback control field 314 in this embodiment.

[0101] In addition, according to specific application requirements, other subfields can be added to Figure 7In the set 401 of sub - fields, as the description information for the LAT feedback control field 314. These other sub - fields may include a dialogue token field (i.e., dialogue token) 410, and this dialogue token 410 indicates the identifier of a specific LAT sequence. These sub - fields may also include a field indicating the channel bandwidth field 414 (i.e., Channel Bandwidth), and this channel bandwidth field 414 indicates the BW of the LAT PPDU. Here, the coding may involve the following values: 20MHz / 40MHz / 80MHz / 160MHz / 320MHz.

[0102] Finally, the reserved sub - field 422 may also be included in the subset 401 of sub - fields.

[0103] According to the above, it should be understood that Example 2 can be combined with Example 1.

[0104] Example 3

[0105] Figure 8 shows another embodiment of the present disclosure. In Figure 6 and Figure 7 and their corresponding descriptions, Figure 8 shows a set 301 of sub - fields according to the third embodiment of the present disclosure, and this set 301 of sub - fields includes a sub - field 316 indicating the set of Per - RU feedback result information. The sub - field 316 has been introduced separately in Figure 6 and Figure 7 respectively. The set 301 of sub - fields has also been introduced separately in Figure 6 and Figure 7 respectively.

[0106] Figure 8 shows that the sub - field 316 may also include a subset 501 of sub - fields, and this subset 501 of sub - fields includes: a sub - field 510 indicating the identity of an element, i.e., the element ID. For the extension, the subset 501 of sub - fields also includes a sub - field 512 indicating the extension of the element ID. This may be accompanied by a sub - field 514 indicating the length (Length) of the element. In addition, the set of sub - fields includes one or more sub - fields 516 indicating the feedback result of the corresponding RU index, i.e., the RU index feedback result information field. Here, the number of information fields included in the set of Per - RU feedback result information fields 516 depends at least on: the bandwidth of the channel (i.e., Channel Bandwidth); the size of the RU corresponding to the measurement metric; a bitmap indicating which RUs the responding STAs 110, 112, 114, 116, 118 have measured, where the valid RU index is set to 1, indicating the RU corresponding to the measurement metric.

[0107] Example 4

[0108] Figure 9 Another embodiment of the present disclosure is shown that presents detailed information about the RU bitmap indication subfield with respect to Figure 7 . Figure 10 Further details are shown in accordance with Figure 9 . According to the first option, as described above, the RU bitmap indication includes 16 bits. Here, the valid RU index depends on the RU granularity, as shown in the table in Figure 9 . Figure 9 The RU granularity (i.e., the RU size corresponding to the measurement metric) is shown; the corresponding encoding is performed using the following values: 20 MHz / 40 MHz / 80 MHz / 160 MHz / 320 MHz. Figure 9 The second column of the table in

[0109] Figure 10 indicates the corresponding range of valid RU indices. Here, for this table, the bit value of each valid RU index can be set to 0 or 1. Conversely, for the bit value of an invalid RU index, for each invalid index of the RU, the bit value of the invalid index of the RU is determined as follows: (i) set the bit value to 0; or (ii) for each invalid index, copy the bit value corresponding to all valid indices. Figure 10 The schematic diagram shown in Figure 9 is based on Embodiment 2 and shows a method for indicating invalid RU indices in the RU bitmap for each selected RU granularity. In Figure 10 , the white squares represent valid RU indices and the gray squares represent invalid RU indices. Here, corresponding to Figure 10 , at a 20 MHz granularity, there are 16 valid RU indices, corresponding to the 16 bits in Figure 10 , i.e., bits 0 to 15. At a 40 MHz granularity, there are 8 valid RU indices, corresponding to the first eight bits, i.e., bits 0 to 7. The remaining 8 bits (i.e., bits 8 to 15) indicate the invalid RU indices at 40 MHz in Figure 10 . Similarly, at an 80 MHz granularity, there are 4 valid RU indices, corresponding to the first four bits in Figure 10 , i.e., bits 0 to 3. The remaining 12 bits (i.e., bits 4 to 15) indicate the invalid RU indices at 80 MHz in Figure 10 . In addition, at a 160 MHz granularity, there are 2 valid RU indices, corresponding to the first two bits, i.e., bits 0 and 1. The remaining 14 bits (i.e., bits 3 to 15) indicate the invalid RU indices at 160 MHz in Figure 10 . Finally, at a 320 MHz granularity, there is 1 valid RU index, corresponding to the first bit, i.e., bit 0. The remaining 15 bits (i.e., bits 1 to 15) indicate the invalid RU indices at 320 MHz in Figure 10 . It should be noted that the invalid indices are ignored by the receiver.

[0110] According to the second option, the RU bitmap indication includes 16 bits, similar to the first option. Here, the valid RU index depends on the RU granularity, as shown in the table in Figure 11 . Figure 11 The RU granularity (i.e., the RU size corresponding to the measurement metric) is shown; the corresponding values are encoded using: 20 MHz / 40 MHz / 80 MHz / 160 MHz / 320 MHz. Figure 11 The second column of the table in Figure 11 indicates the corresponding values of the valid RU index. Here, for this table, the bit value of each valid RU index can be set to 0 or 1. Conversely, the bit value of the invalid RU index is determined as follows: (i) set the value of the bit to 0; or (ii) for the same RU granularity, set the nearest valid index to be less than the invalid index. Then set the value of the bit to the bit value determined by the nearest valid index less than the invalid index for the same RU granularity. For example, according to the table shown in

[0111] below, Figure 12 The following schematic diagram is based on Embodiment 2 and shows the indication of the invalid RU index in the RU bitmap for each selected RU granularity. In Figure 12 , the white squares represent the valid RU index and the gray squares represent the invalid RU index. Here, corresponding to Figure 10 , at 20 MHz granularity, there are 16 valid RU indices, corresponding to the 16 bits in Figure 10 , i.e., bits 0 to 15. At 40 MHz granularity, there are 8 valid RU indices. These 8 valid RU indices are indicated by bits 0, 2, 4, 6, 8, 10, 12, 14. The remaining 8 bits (i.e., bits 1, 3, 5, 7, 9, 11, 13, and 15) indicate the invalid RU indices at 40 MHz in Figure 12 . Similarly, at 80 MHz granularity, there are 4 valid RU indices, corresponding to bits 0, 4, 8, and 12. The remaining 12 bits (i.e., bits 1, 2, 3, 5, 6, 7, 9, 10, 11, 13, 14, and 15) indicate the invalid RU indices at 80 MHz in Figure 12 . In addition, at 160 MHz granularity, there are 2 valid RU indices, corresponding to bits 0 and 8. The remaining 14 bits (i.e., bits 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, and 15) indicate the invalid RU indices at 160 MHz in Figure 12 . Finally, at 320 MHz granularity, there is 1 valid RU index, corresponding to the first bit, i.e., bit 0. The remaining 15 bits (i.e., bits 1 to 15) indicate the invalid RU indices at 320 MHz in Figure 12Invalid RU index at 320 MHz in China.

[0112] In any case, it should be understood that the values in the invalid index are ignored by the receiver.

[0113] Embodiment 5

[0114] In another embodiment of the present disclosure, Figure 13 Further details of the per-RU feedback result information field 516 according to the fifth embodiment of the present disclosure are shown. The per-RU feedback result information field 516 was introduced in Embodiment 3. In Figure 8 Subset 501 of subfields was also introduced in Embodiment 3 of. It can be seen that Embodiment 5 can be combined with Embodiment 3.

[0115] As Figure 13 shown, the per-RU feedback result information field 516 includes a subset 601 of subfields. The subset 601 of subfields includes at least the following subfields: a subfield 610 (i.e., RU Index (RUIndex)) indicating the RU index referred to by the field information. A subfield 612 (i.e., PHY Rate Info Length), which provides a value within the range 0 to 15 and indicates the number of PHY rate indices included in the set of PHY rate indices (subfield 614) for this specific RU. Subfield 614 (i.e., the set of PHY rate indices) refers to a set of M PHY rate indices <MCS, N SS > tuple, where a codeword is sent for each RU of the user.

[0116] The set 601 of subfields also includes a number of fields 616-1,..., 616-k, which refer to a set of measurement metrics. Here, the number k is a positive integer. The exact number of the set depends on the measurement metrics indicated as non-zero values in the measurement metric information bitmap in the previous LAT announcement frame, see Figure 7 Subfield 420 in.

[0117] Figure 13 An example of the set of measurement metrics is shown, denoted by 701. Here, the first field 616-1, i.e., the extended field, is shown. It should be understood that other fields can be selected. The set 616-1 includes fields 716-1,..., 716-M related to the M PHY rate indices, where M is a positive integer. Each field includes the measured values of the first set of measurement metrics.

[0118] Embodiment 6

[0119] In another embodiment of the present disclosure, Figure 14Shows a single set of metrics for the Per-RU feedback result information field according to the sixth embodiment of the present disclosure. Figure 14 And its embodiments are closely related to Figure 13 And its corresponding embodiments, so that Figure 13 The embodiments of Figure 14 And the embodiments of Figure 13 Can be combined. It should be noted that, generally, the sub-fields 510', 512', 514' and 516' correspond to or are the same as the sub-fields in Figure 13 . Similarly, the sub-fields 610', 612', 614' and 616-1' are the same as the sub-fields in Figure 13 . A subset of the sub-field 501' corresponds to a subset of the sub-field 501 in Figure 13 , but this subset has a single RU index feedback result information field, so a specific length selection is made in the length field. Similarly, a subset of the sub-field 601' corresponds to the sub-field 601 in

[0120] In Figure 14 In the example shown, for each valid value of the metric, we may have, for example: Metric 1 - the number of erroneous bits per codeword (EBPC), where 0 to 253 indicate the number of erroneous bits, and 254 indicates at least 254 erroneous bits.

[0121] Here, invalid / N / A values are indicated separately. For example, if the metric value includes 1 byte, the value 255 is used, where the measurement metric is encoded as "01" in the LAT advertisement / Per-STA Info. If the metric value includes 2 bytes, the value 65535 is used, where the measurement metric is encoded as "10" in the LAT advertisement / Per-STA Info.

[0122] In Figure 14 In the example, the following are the parameters of a specific non-AP STA measured for Metric 1: RU index = 1, PHY rate length = 4, PHY rate indices: 10, 20, 50, N / A, measured values of Metric 1: 10, 0, 255, 255. Figure 14 The example in

[0123] Example 7

[0124] Figure 15 Another embodiment of the present disclosure is shown. Figure 15 A link adaptation training (LAT) feedback frame is provided for multi-user operation mode (MU mode) in a wireless local access network. Figure 15 The method shown is a method for providing a link adaptation training (LAT) feedback frame in a wireless local access network (WLAN), and the method includes: Step 450: sending a LAT announcement frame from a requesting STA to one or more responding STAs, wherein a link adaptation physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; Step 451: sending a dedicated trigger frame (TF) from the requesting STA to one or more responding STAs, wherein the dedicated TF triggers the sending of a LAT feedback frame after a predefined inter frame space (IFS), and the LAT feedback frame is sent by one or more responding STAs provided that one or more responding STAs have been included in the per station information (Per-STA Info) for the corresponding responding STA in the LAT announcement frame; Step 453: the requesting STA receiving a LAT feedback frame from one or more responding STAs, wherein the LAT feedback frame is a management frame of the "Action NoAck" subtype; the LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category (ActionCategory); a field indicating an action category value corresponding to the action category.

[0125] Figure 15 A method for providing a link adaptation training (LAT) feedback frame in a wireless local access network (WLAN) in a multi-user scenario is shown. Next Figure 16 A corresponding method for providing feedback to a requesting STA in a single-user scenario is shown.

[0126] Figure 16Disclosed is a method for providing link adaptation training (LAT) feedback frames for single-user operation mode (SU mode) in a wireless local access network (WLAN). The WLAN includes a requesting station (STA) and a responding STA. The method includes: Step 550: Sending an LAT announcement frame from the requesting STA to the responding STA, where a link adaptation training physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; Step 551: The requesting STA receives an LAT feedback frame. After determining that the previously received LAT announcement frame by the responding STA only includes a single per station information (Per-STA Info) for the responding STA and is followed by a link adaptation training physical layer protocol data unit (LAT-PPDU), after a predefined inter frame space (IFS), the LAT feedback frame is sent from the responding STA. The LAT feedback frame is a management frame of the "Action No Ack" subtype; The LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0127] Embodiment 8

[0128] Figure 17 Another embodiment of the present disclosure is shown. Figure 17FIG. 0 shows an apparatus 30 in a wireless local access network (WLAN), the WLAN including a requesting station (STA) and one or more responding STAs, each of the one or more responding STAs including a sending unit 3501, wherein the sending unit 3501 is configured to: send a LAT feedback frame from the one or more responding STAs to the requesting STA (105), wherein the sending starts after a predefined inter frame space (IFS) after each of the responding STAs in the responding STAs receives a dedicated trigger frame (TF) for the corresponding responding STA from the requesting STA; the TF follows a link adaptation training physical layer protocol data unit (LAT-PPDU); before the LAT-PPDU is a LAT announcement frame determined by the corresponding responding STA to include per station information (Per-STA Info) for the corresponding responding STA, wherein the LAT feedback frame is a management frame of the "Action No Ack" subtype; the LAT feedback frame includes a frame body, wherein the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0129] Embodiment 9

[0130] Figure 18 FIG. 7 shows another embodiment of the present disclosure. Figure 18A device 30 in a wireless communication network (WLAN) is shown. The WLAN includes a requesting station (STA) and a responding STA. Among them, the requesting STA includes a sending unit 3502. The sending unit 3502 is configured to: The responding STA sends a LAT feedback frame to the requesting STA. The sending starts after a predefined inter frame space (IFS) after the responding STA finishes receiving a link adaptation training physical layer protocol data unit (LAT-PPDU). The LAT-PPDU is received after the responding STA determines that the previous LAT advertisement frame includes only a single per station information (Per-STA Info) for the responding STA. The LAT feedback frame is a management frame of the "Action No Ack" subtype; The LAT feedback frame includes a frame body. The frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0131] Embodiment 10

[0132] Figure 19 Another embodiment of the present disclosure is shown. Figure 19A device 20 in a wireless local access network (WLAN) is shown. The WLAN includes a station (STA) and one or more responding STAs. Among them, the requesting STA includes a sending unit 4501 and a receiving unit 4503. The sending unit 4501 is configured to: send a LAT announcement frame from the requesting STA to one or more responding STAs, where a link adaptation physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; send a dedicated trigger frame (TF) from the requesting STA to one or more responding STAs, where the dedicated TF triggers the sending of a LAT feedback frame after a predefined inter frame space (IFS), and the LAT feedback frame is sent by one or more responding STAs provided that one or more responding STAs have been included in the per station information (Per-STA Info) for the corresponding responding STA in the LAT announcement frame; The receiving unit 4503 is configured to: receive a LAT feedback frame from one or more responding STAs, where the LAT feedback frame is a management frame of the "Action No Ack" subtype; The LAT feedback frame includes a frame body, and the frame body includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

[0133] Embodiment 11

[0134] Figure 20 Another embodiment of the present disclosure is shown. Figure 20A device 20' in a wireless local access network (WLAN) is shown. The WLAN includes a station (STA) and a responding STA. Among them, the requesting STA includes a sending unit 4502 and a receiving unit 4504. The sending unit 4502 is used to: send a LAT announcement frame from the requesting STA to the responding STA, where a link adaptation training physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; The receiving unit 4504 is used to: receive a LAT feedback frame. After determining that the previously received LAT announcement frame by the responding STA only includes a single per station information (Per-STA Info) for this responding STA and is followed by a link adaptation training physical layer protocol data unit (LAT-PPDU), after a predefined inter frame space (IFS), the LAT feedback frame is sent from the responding STA. The LAT feedback frame is a management frame of the "Action NoAck" subtype; The LAT feedback frame includes a frame body, and the frame body includes: a field indicating the Action Category; a field indicating the action category value corresponding to the action category.

[0135] Abbreviations

[0136] ·ACK: Acknowledge

[0137] ·AP: Access Point

[0138] ·BA[CK]: Block-ACK: In 802.11, the receiver should usually respond to data transmission with an ACK; if multiple frames are transmitted within a single PPDU, each frame must be acknowledged.

[0139] ·BCC: Binary Convolutional Coding

[0140] ·BER: Bit Error Rate

[0141] ·BSS: Basic Serving Set

[0142] ·CQI: Channel Quality Indicator

[0143] ·EHT: Extremely HT

[0144] ·HE: High Efficiency

[0145] ·HLA: HE Link Adaptation

[0146] ·HT: High Throughput

[0147] ·LA: Link Adaptation

[0148] ·LAT: LA Training

[0149] ·LDPC: Low-Density Parity Check

[0150] ·MAC: Medium Access Control

[0151] ·MCS: Modulation&Coding Scheme

[0152] ·MFB: MCS Feedback

[0153] ·ML: Multi Link

[0154] ·MLD: ML Device

[0155] ·MLO: ML Operation

[0156] ·MSDU: MAC Service Data Unit

[0157] ·MU: Multi User

[0158] ·N_SS: Number of Spatial Streams

[0159] · PER: Packet Error Rate

[0160] · PHY: Physical Layer

[0161] · PPDU: PHY Protocol Data Unit

[0162] · RU: Resource Unit

[0163] · SNR: Signal-to-Noise Ratio

[0164] · STA: Station (in general, it can be an AP STA or a non-AP STA)

[0165] · SU: Single User

[0166] · TF: Trigger Frame: In 802.11ax, the trigger frame is introduced as a way to trigger one or more STAs to synchronously transmit with the trigger AP

[0167] · WLAN: Wireless Local Access Network

Claims

1. A method for providing Link Adaptation Training (LAT) feedback frames in a Wireless Local Area Network (WLAN) (100), characterized in that, the WLAN (100) includes a requesting Station (STA) (105) and one or more responding STAs (110, 112, 114, 116, 118), and the method includes: (251) The one or more responding STAs (110, 112, 114, 116, 118) send LAT feedback frames (201) to the requesting STA (105), wherein the sending starts after a predefined Inter-Frame Space (IFS) after each of the responding STAs in the responding STAs receives a dedicated Trigger Frame (TF) for the corresponding responding STA from the requesting STA; the TF follows a Link Adaptation Training Physical Layer Protocol Data Unit (LAT-PPDU); before the LAT-PPDU is a LAT announcement frame, which is determined by the corresponding responding STA to include per-Station Information (Per-STAInfo) for the corresponding responding STA, wherein, the LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; the LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

2. A method for providing Link Adaptation Training (LAT) feedback frames in a Wireless Local Area Network (WLAN) (100), characterized in that, the WLAN (100) includes a requesting Station (STA) (105) and responding STAs (110, 112, 114, 116, 118), and the method includes: (351) The responding STAs (110, 112, 114, 116, 118) send LAT feedback frames (201) to the requesting STA (105), wherein the sending starts after a predefined Inter-Frame Space (IFS) after the responding STAs complete receiving a Link Adaptation Training Physical Layer Protocol Data Unit (LAT-PPDU), wherein the LAT-PPDU is received after the responding STAs determine that a previous LAT announcement frame includes only a single per-Station Information (Per-STA Info) for the responding STAs, wherein, the LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; the LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

3. The method according to claim 1 or 2, characterized in that, the frame body (212) of the LAT feedback frame (201) further includes: a LAT feedback control field (314) including a set of parameters related to the measurements on which the LAT feedback from the responding STAs (110, 112, 114, 116, 118) is based; Field (316) containing a set of per-resource unit (RU) feedback result information: Per-RU feedback result information set, where the Per-RU feedback result information set contains link performance metrics measured by the responding STA (110, 112, 114, 116, 118): Measured metrics.

4. The method according to claim 3, wherein, the LAT feedback control field (314) at least includes the following sub-fields: Sub-field (412) indicating the index of the codeword: Codeword index, where the codeword index indicates the codeword used for the LAT; Sub-field (416) indicating the size of the RU corresponding to the measured metrics included in each Per-RU feedback result information field; Sub-field (418) including a bitmap indicating which RUs the responding STA (110, 112, 114, 116, 118) has measured; Sub-field (420) including a bitmap indicating which metrics the responding STA (110, 112, 114, 116, 118) has measured and fed back.

5. The method according to claim 3 or 4, wherein, the Per-RU feedback result information set (316) at least includes the following fields: Sub-field (510) indicating the element ID; Sub-field (512) indicating the element ID extension; Sub-field (514) indicating the length: Length; One or more Per-RU feedback result information fields (516).

6. The method according to claim 5, wherein, the number of information fields included in the set of Per-RU feedback result information fields (516) depends at least on: The bandwidth of the channel (channel bandwidth); The size of the RU corresponding to the measured metrics; The bitmap indicating which RUs the responding STA (110, 112, 114, 116, 118) has measured, where The valid RU index is set to 1, indicating the RU corresponding to the measured metrics.

7. The method according to claim 5 or 6, wherein, each Per-RU feedback result information field in the Per-RU feedback result information fields (516) at least includes the following sub-fields: Sub-field (610) indicating the index of the RU: RU index; Sub-field (614) indicating the set of PHY rates obtained after measuring each reported metric; Sub-field (612) containing the number M, where the number M indicates the number of PHY rates included in the set of PHY rate indices, and M is an integer in the range of 0 to 15; Sub-field (616-1,..., 616-k) containing k sets of measured metrics, where k is an integer greater than 0.

8. The method according to claim 7, wherein, For a set of measured metrics x, where x = 1, 2, ……, k, the measured values of metric x are provided according to each PHY rate indicated in the set of PHY rate indices (614), wherein the size of the subfield representing each metric value depends on the type of the measured metric and is indicated as a non-zero value in the LAT feedback control field (314) or in the measured metric information bitmap subfield (420), where: Value 01 indicates that the size of the metric value is represented by one byte; Value 10 indicates that the size of the metric value is represented by two bytes.

9. The method according to claim 7 or 8, characterized in that, the number of error bits of each codeword is used as a measured metric, wherein the valid value of the measured metric is an integer within the range of 0 to 254, wherein values 0 to 253 correspondingly indicate the number of error bits, and value 254 indicates at least 254 error bits.

10. The method according to any one of claims 7 to 9, characterized in that, the invalid value corresponding to each measured metric is indicated by the following values: If the metric value is represented by a one-byte subfield, it is value 255; If the metric value is represented by a two-byte subfield, it is value 65535.

11. A method for providing link adaptation training (LAT) feedback frames in a wireless local area network (WLAN), characterized in that, the WLAN includes a requesting station (STA) (105) and one or more responding STAs (110, 112, 114, 116, 118), and the method includes: (450) Sending an LAT announcement frame from the requesting STA (105) to the one or more responding STAs (110, 112, 114, 116, 118), wherein a link adaptation physical layer protocol data unit (LAT-PPDU) follows the LAT announcement frame; (451) Sending a dedicated trigger frame (TF) from the requesting STA (105) to the one or more responding STAs (110, 112, 114, 116, 118), wherein the dedicated TF triggers the sending of an LAT feedback frame after a predefined inter-frame spacing (IFS), and the LAT feedback frame is sent by the one or more responding STAs (110, 112, 114, 116, 118) provided that the one or more responding STAs (110, 112, 114, 116, 118) have been included in the per-station information (Per-STA Info) for the corresponding responding STA in the LAT announcement frame; (453) The requesting STA (105) receiving the LAT feedback frame (201) from the one or more responding STAs (110, 112, 114, 116, 118), wherein, the LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; the LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: a field indicating the action category; a field indicating the action category value corresponding to the action category.

12. A method for providing Link Adaptation Training (LAT) feedback frames in a Wireless Local Area Network (WLAN) (100), characterized in that, the WLAN (100) includes a requesting Station (STA) (105) and responding STAs (110, 112, 114, 116, 118), and the method includes: (550) sending an LAT announcement frame from the requesting STA (105) to the responding STAs (110, 112, 114, 116, 118), wherein a Link Adaptation Training Physical Layer Protocol Data Unit (LAT-PPDU) follows the LAT announcement frame; (551) the requesting STA (105) receiving an LAT feedback frame (201), wherein after determining that a previous LAT announcement frame received by the responding STAs (110, 112, 114, 116, 118) includes only per-Station Information (Per-STA Info) for the respective responding STA and is followed by a Link Adaptation Training Physical Layer Protocol Data Unit (LAT-PPDU), after a predefined Inter-Frame Space (IFS), the LAT feedback frame (201) is sent from the responding STAs (110, 112, 114, 116, 118), wherein, the LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; the LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: a field indicating an action category; a field indicating an action category value corresponding to the action category.

13. An apparatus in a Wireless Local Area Network (WLAN), characterized in that, the WLAN includes a requesting Station (STA) (105) and one or more responding STAs (110, 112, 114, 116, 118), wherein the one or more responding STAs (110, 112, 114, 116, 118) are configured to: send an LAT feedback frame (201) to the requesting STA (105), wherein the sending starts after a predefined Inter-Frame Space (IFS) after each of the responding STAs in the responding STAs receives a dedicated Trigger Frame (TF) for the respective responding STA from the requesting STA; the TF follows a Link Adaptation Training Physical Layer Protocol Data Unit (LAT-PPDU); the LAT-PPDU is preceded by an LAT announcement frame, which the respective responding STA determines to include per-Station Information (Per-STA Info) for the respective responding STA, wherein, the LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; the LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: a field (310) indicating an action category; a field (312) indicating an action category value corresponding to the action category.

14. A device in a Wireless Local Area Network (WLAN), characterized in that, the WLAN includes a Requesting Station (STA) (105) and Responding STAs (110, 112, 114, 116, 118), wherein the Responding STAs (110, 112, 114, 116, 118) are configured to: the Responding STAs (110, 112, 114, 116, 118) send a Link Adaptation Training (LAT) feedback frame (201) to the Requesting STA (105), wherein the sending starts after a predefined Inter-Frame Space (IFS) following the completion of the reception of the Link Adaptation Training Physical Layer Protocol Data Unit (LAT-PPDU) by the Responding STA, and wherein the LAT-PPDU is received after the Responding STA determines that a previous LAT announcement frame includes only a single Per-Station Information (Per-STA Info) for the Responding STA, and wherein, the LAT feedback frame (201) is a management frame of the "No Acknowledgment Action" subtype; the LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: a field (310) indicating the action category; a field (312) indicating the action category value corresponding to the action category.

15. The device according to claim 13 or 14, characterized in that, the frame body (212) of the LAT feedback frame (201) further includes: a LAT feedback control field (314) including a set of parameters, the set of parameters being related to the measurements on which the LAT feedback from the Responding STA (110, 112, 114, 116, 118) is based; a field (316) containing a set of Per-Resource Unit (RU) feedback result information: Per-RU feedback result information set, the Per-RU feedback result information set containing link performance metrics measured by the Responding STA (110, 112, 114, 116, 118): measurement metrics.

16. The device according to claim 15, characterized in that, the LAT feedback control field (314) at least includes the following sub-fields: a sub-field (412) indicating the index of the codeword: codeword index, the codeword index indicating the codeword used for the LAT; a sub-field (416) indicating the size of the RU corresponding to the measurement metrics included in each Per-RU feedback result information field; a sub-field (418) including a bitmap indicating which RUs the Responding STA (110, 112, 114, 116, 118) has measured; a sub-field (420) including a bitmap indicating which metrics the Responding STA (110, 112, 114, 116, 118) has measured and feedback.

17. The device according to claim 15 or 16, characterized in that, the Per-RU feedback result information set at least includes the following fields: a sub-field (510) indicating the element ID; a sub-field (512) indicating the element ID extension; a sub-field (514) indicating the length: length; One or more per-RU feedback result information fields (516).

18. The apparatus according to claim 17, wherein, the number of information fields included in the set of the per-RU feedback result information fields (516) depends at least on: the bandwidth of the channel (channel bandwidth); the size of the RU corresponding to the measurement metric; a bitmap indicating which RUs are measured by the responding STA (110, 112, 114, 116, 118), wherein, the valid RU index is set to 1, indicating the RU corresponding to the measurement metric.

19. The apparatus according to claim 17 or 18, wherein, each per-RU feedback result information field in the per-RU feedback result information fields (516) includes at least the following sub-fields: a sub-field (610) indicating the index of the RU: RU index; a sub-field (614) indicating the set of PHY rates obtained after measuring each reported metric; a sub-field (612) containing a number M, the number M indicating the number of PHY rates included in the set of PHY rate indices, wherein M is an integer in the range of 0 to 15; a sub-field (616-1,..., 616-k) containing k sets of measurement metrics, wherein k is an integer greater than 0.

20. The apparatus according to claim 19, wherein, for the set of measurement metrics x, where x = 1, 2,..., k, the measured value of metric x is provided according to each PHY rate indicated in the set of PHY rate indices (614), wherein the size of the sub-field representing each metric value depends on the type of the measurement metric and is indicated as a non-zero value in the LAT feedback control field (314) or in the measurement metric information bitmap sub-field (420), wherein: value 01 indicates that the size of the metric value is represented by one byte; value 10 indicates that the size of the metric value is represented by two bytes.

21. The apparatus according to claim 19 or 20, wherein, the number of error bits of each codeword is used as a measurement metric, wherein the valid value of the measurement metric is an integer in the range of 0 to 254, wherein values 0 to 253 indicate the number of error bits accordingly, and value 254 indicates at least 254 error bits.

22. The apparatus according to any one of claims 19 to 21, wherein, the invalid value corresponding to each measurement metric is indicated by the following values: value 255 if the metric value is represented by a one-byte sub-field; value 65535 if the metric value is represented by a two-byte sub-field.

23. An apparatus in a wireless local area network WLAN, wherein, the WLAN includes a requesting station STA (105) and one or more responding STAs (110, 112, 114, 116, 118), wherein the requesting STA (105) is configured to: Send a LAT announcement frame from the requesting STA (105) to the one or more responding STAs (110, 112, 114, 116, 118), where a link adaptation training physical layer protocol data unit LAT-PPDU follows the LAT announcement frame; Send a dedicated trigger frame TF from the requesting STA (105) to the one or more responding STAs (110, 112, 114, 116, 118), where the dedicated TF triggers the transmission of a LAT feedback frame after a predefined inter-frame space IFS, and the LAT feedback frame is sent by the one or more responding STAs (110, 112, 114, 116, 118) provided that each station information Per-STA Info for the corresponding responding STA in the LAT announcement frame has been included in the one or more responding STAs (110, 112, 114, 116, 118); Receive the LAT feedback frame (201) from the one or more responding STAs (110, 112, 114, 116, 118), where The LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; The LAT feedback frame (201) includes a frame body (212), where the frame body (212) includes: A field (310) indicating an action category; A field (312) indicating an action category value corresponding to the action category.

24. A device in a wireless local area network WLAN (100), Characterized in that The WLAN (100) includes a requesting station STA (105) and responding STAs (110, 112, 114, 116, 118), where the requesting STA (105) is used for: Send a LAT announcement frame from the requesting STA (105) to the responding STAs (110, 112, 114, 116, 118), where a link adaptation training physical layer protocol data unit LAT-PPDU follows the LAT announcement frame; The requesting STA (105) receives a LAT feedback frame (201), where after determining that the previous LAT announcement frame received by the responding STA (110, 112, 114, 116, 118) includes only a single per-station information Per-STA Info for the corresponding responding STA and is followed by a link adaptation training physical layer protocol data unit LAT-PPDU, after a predefined inter-frame space IFS, the LAT feedback frame (201) is sent from the responding STA (110, 112, 114, 116, 118), where The LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; The LAT feedback frame (201) includes a frame body (212), where the frame body (212) includes: A field indicating an action category; A field indicating an action category value corresponding to the action category.

25. A computer program product including program code, Characterized in that, When the program code is executed on a computer or a processor, it is used to execute the method according to any one of the above claims 1 to 12.

26. A non-transitory computer-readable medium carrying program code, Characterized in that, When the program code is executed by a computer device, the computer device is caused to execute the method according to any one of claims 1 to 12.

27. A device in a wireless local area network WLAN, Characterized in that, The WLAN includes a requesting station STA (105) and one or more responding STAs (110, 112, 114, 116, 118) each including a transmitting unit (3501), wherein the transmitting unit (3501) is configured to: The one or more responding STAs (110, 112, 114, 116, 118) send a LAT feedback frame (201) to the requesting STA (105), wherein the sending starts after a predefined inter-frame space IFS after each of the responding STAs in the responding STAs receives a dedicated trigger frame TF for the corresponding responding STA from the requesting STA; the TF follows a link adaptation training physical layer protocol data unit LAT-PPDU; before the LAT-PPDU is a LAT announcement frame, and the LAT announcement frame is determined by the corresponding responding STA to include per-station information Per-STAInfo for each station corresponding to the corresponding responding STA, wherein, The LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; The LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: A field (310) indicating an action category; A field (312) indicating an action category value corresponding to the action category.

28. A device in a wireless local area network WLAN, Characterized in that, The WLAN includes a requesting station STA (105) and STAs (110, 112, 114, 116, 118) each including a transmitting unit (3502), wherein the transmitting unit (3502) is configured to: The responding STAs (110, 112, 114, 116, 118) send a LAT feedback frame (201) to the requesting STA (105), wherein the sending starts after a predefined inter-frame space IFS after the responding STAs complete receiving a link adaptation training physical layer protocol data unit LAT-PPDU, wherein the LAT-PPDU is received after the responding STAs determine that a previous LAT announcement frame includes only a single per-station information Per-STA Info for the responding STAs, wherein, The LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; The LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: A field (310) indicating an action category; A field (312) indicating an action category value corresponding to the action category.

29. A device in a Wireless Local Area Network (WLAN), characterized in that, the WLAN includes a requesting Station (STA) (105) and one or more responding STAs (110, 112, 114, 116, 118), wherein the requesting STA (105) includes: a sending unit (4501) for: sending a Link Adaptation Training (LAT) announcement frame from the requesting STA (105) to the one or more responding STAs (110, 112, 114, 116, 118), wherein a Link Adaptation Training Physical Layer Protocol Data Unit (LAT-PPDU) follows the LAT announcement frame; sending a dedicated Trigger Frame (TF) from the requesting STA (105) to the one or more responding STAs (110, 112, 114, 116, 118), wherein the dedicated TF triggers the sending of a LAT feedback frame after a predefined Inter-Frame Space (IFS), and the LAT feedback frame is sent by the one or more responding STAs (110, 112, 114, 116, 118) provided that each Station Information (Per-STA Info) for the corresponding responding STA in the LAT announcement frame already includes the one or more responding STAs (110, 112, 114, 116, 118); a receiving unit (4503) for receiving the LAT feedback frame (201) from the one or more responding STAs (110, 112, 114, 116, 118), wherein, the LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; the LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: a field (310) indicating an action category; a field (312) indicating an action category value corresponding to the action category.

30. A device in a Wireless Local Area Network (WLAN), characterized in that, the WLAN includes a requesting Station (STA) (105) and a responding STA (110, 112, 114, 116, 118), wherein the requesting STA (105) includes: a sending unit (4502) for sending a Link Adaptation Training (LAT) announcement frame from the requesting STA to the responding STA, wherein a Link Adaptation Training Physical Layer Protocol Data Unit (LAT-PPDU) follows the LAT announcement frame; A receiving unit (4504) for receiving a LAT feedback frame (201), wherein after determining that a previous LAT announcement frame received by the responding STA (110, 112, 114, 116, 118) includes only a single per-station information (Per-STA Info) for the corresponding responding STA and is followed by a link adaptation training physical layer protocol data unit (LAT-PPDU), after a predefined inter-frame space (IFS), the LAT feedback frame (201) is sent from the responding STA (110, 112, 114, 116, 118), wherein the LAT feedback frame (201) is a management frame of the "no acknowledgment action" subtype; the LAT feedback frame (201) includes a frame body (212), wherein the frame body (212) includes: a field (310) indicating an action category; a field (312) indicating an action category value corresponding to the action category.

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