Fast link adaptation: codework design and alignment for training ppdu

Abstract

The present invention relates to a method of link adaptation in a wireless communication network, the wireless communication network comprising at least one initiator and responders, the method comprising: transmitting to the one or more responders a training data packet comprising a set of predefined bit sequences, where the predefined bit sequences are encoded into codewords, the present invention relates to a method for encoding a plurality of codewords, the codewords being modulated using one or more modulation and coding schemes (MCS), each modulated codeword being mapped onto one or more predefined frequency sub-bands in a predetermined manner, the frequency sub-bands having a predefined number of sub-carriers, the sub-carriers spanning one or more OFDM symbols; receiving a feedback report of each of the responders, the feedback report comprising a value of a measured link performance indicator related to each codeword sent to the respective responder; and according to the reported feedback, adjusting transmission scheme parameters of subsequent data packets on the communication link between the initiator and the one or more responders.

Description

Technical Field

[0001] Embodiments of the present invention generally relate to the field of fast link adaptation in wireless network communication systems. Background Art

[0002] Advanced Wi-Fi standards such as 802.11ax and 802.11be support very high data rates, for example, 4.8Gbps to 23Gbps. Link Adaptation (LA) is a mechanism to adjust the transmission (TX) scheme and parameters, such as the PHY rate, number of streams, and frequency allocation (Resource Unit (RU) selection) specified by the Modulation Coding Scheme (MCS). This adjustment attempts to optimally adapt the parameters to the instantaneous conditions of the wireless link, such as 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 definition parameters are slowly changed through a "trial and error" process based on the reception confirmation (ACK) of the sent data packets reported by the receiver (RX). The "slow" here means that it may take a long time for the algorithm to converge to the optimal set of parameters to achieve a certain predefined indicator target, such as packet error rate (PER) = 10%. The word "optimal" here should be viewed from the perspective of long-term average.

[0004] In addition to ACK, several other LA-assisted feedback types are supported in the WLAN IEEE 802.11 standard specification today, such as:

[0005] (i) Signal to Noise Ratio (SNR) per resource unit (RU) (channel quality indicator (CQI)): The station (STA) can be instructed to calculate the SNR of a specific RU based on the null data packet (NDP) and feed it back to the initiating access point (AP). However, the question is whether the AP can trust the calculation performed on the STA side. For example, considering the receiver implementation of a specific STA, the following questions may arise: what is the relationship between SNR and link performance, and what impact this relationship has on the calculation.

[0006] (ii) MCS Feedback (MFB): A STA can indicate its preferred MCS. This may be an acceptable indicator because it takes into account the STA's implementation. However, this approach is not usually implemented, and the WLAN specification (i.e., WLAN IEEE 802.11) does not specify / 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 portion of any data or management frame sent by a non-AP STA. When any HESTA indicates a specific LA control message as a High-Efficiency (HE) variant, a specific LA control message may be added in the High-Throughput (HT) control portion.

[0008] To reduce the LA convergence time, a new approach is needed. This new approach should provide the initiator with a reliable estimate of the expected link performance as quickly as possible, at least for several MCS and RU combinations. The focus should be on the coding bit error rate (BER) as the link performance indicator that the responding STA feeds back to the initiator. Summary of the invention

[0009] The invention relates to a communication method and a device used in the field of fast link adaptation in a wireless network communication system.

[0010] The invention is defined by the scope of the independent claim. Some advantageous embodiments are provided in the dependent claims.

[0011] According to a first aspect, a method for link adaptation in a wireless communication network is provided. The wireless communication network includes at least one initiator and one or more responders, and the method includes: the initiator sends a training data packet including a set of predefined bit sequences to the one or more responders, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCS), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency-division multiplexing (OFDM) symbols; the initiator receives a feedback report from each of the responders, wherein the feedback report includes a value of a measured link performance indicator related to each codeword sent to the corresponding responder; and according to the reported feedback, adjusting the transmission scheme parameters of subsequent data packets on the communication link between the initiator and the one or more responders.

[0012] In the following, it should be understood that N SS , N_SS and N_SS can all be used to indicate the number of spatial streams.

[0013] Therefore, the initiator sends a physical protocol data unit (PPDU) including a set of predefined (i.e. known) codewords to one or more responders. The sending initiator entity should use a different MCS for each RU of one or more allocated RUs (i.e. single or multiple RUs). In other words, the sending initiator should use different MCS values ​​within each RU. The responder should respond with a feedback message that provides measured link performance indicators, such as the number of erroneous bits per codeword or bit error rate (BER). In addition, if necessary, the initiator should be able to "convert" the reported link performance indicators into PER. Therefore, the initiator should be able to quickly understand the expected link performance and can therefore use a specific RU, MCS and number of spatial streams N. SS In the above description, bit error rate (BER) is an example of a link performance indicator.

[0014] Therefore, this approach can be used to shorten the convergence time of ACK-based data-only "external link adaptation" mechanisms (eg, Minstrel).

[0015] According to the first aspect, in a first possible implementation of the method, the wireless communication network is a wireless local access network (WLAN); the initiator and the responder are WLAN devices; the data packet is a physical protocol data unit (PPDU); and the predefined frequency subband is a resource unit (RU).

[0016] According to the first aspect or any of the above implementations of the first aspect, in a second possible implementation of the method, at least two of the modulation codewords included in the training data packet are respectively transmitted by different numbers N SS The spatial stream is used to send.

[0017] According to the first aspect or any of the above implementations of the first aspect, in a third possible implementation of the method, the method further includes: encoding the predefined bit sequence into a codeword using an LDPC or BCC coding scheme respectively; allocating the coded bits including each codeword to N SS spatial streams, wherein each corresponding spatial stream carries a bit stream; each bit stream is further divided into bit subsequences, wherein each bit subsequence consists of N BPSCS bits, N BPSCS is the number of bits per stream per subcarrier; further modulating the bit subsequences comprising each bit stream into quadrature amplitude modulation (QAM) symbol streams that together constitute a modulation codeword; dividing the QAM symbols obtained from each QAM symbol stream into a plurality of groups N SS QAM symbols, each group of which is mapped to a single corresponding subcarrier within the frequency subband or RU to which the modulation codeword is mapped.

[0018] Here, it should be understood that N BPSCS Both N_BPSCS and N_BPSCS can be used to indicate the number of bits per subcarrier per spatial stream.

[0019] According to the first aspect or any of the above implementations of the first aspect, in a fourth possible implementation of the method, the modulation codewords are mapped to RUs spanning several OFDM symbols in a consecutive order.

[0020] According to the first aspect or any of the above implementations of the first aspect, in a fifth possible implementation of the method, the modulation codeword is mapped to an RU spanning several OFDM symbols, so that each modulation codeword starts from a different OFDM symbol.

[0021] According to any one of the fourth or fifth implementations of the first aspect, in a sixth possible implementation of the method, each modulation codeword in the modulation codeword is aligned with the subcarrier so that the number of bits N per spatial stream per subcarrier carried by each subcarrier to which the modulation codeword is mapped BPSCS Exactly the same.

[0022] Here, it should be understood that N BPSCS Both N_BPSCS and N_BPSCS can be used to indicate the number of bits per subcarrier per spatial stream.

[0023] According to the sixth implementation of the first aspect, in a seventh possible implementation of the method, mapping the modulation codeword to the subcarrier includes: using any QAM symbol to fill the unused subcarriers of the frequency subband within the used OFDM symbol.

[0024] According to any one of the fourth or fifth implementations of the first aspect, in an eighth possible implementation of the method, the method further includes: before modulating the codeword, deleting one or more bits at the end of the codeword to align with multiple subcarriers of the OFDM symbol, so that after modulating the codeword, the number of bits N per spatial stream per subcarrier carried by each subcarrier to which the modulated codeword is mapped is BPSCS Exactly the same.

[0025] According to the first aspect or any one of the first or second implementations of the first aspect, in a ninth possible implementation of the method, the method further includes sending the training data packet, including indicating to the responder which modulation codewords and their corresponding MCS and N by including overhead SS Sent in the training data packet.

[0026] According to the ninth implementation manner of the first aspect, in a tenth possible implementation manner of the method, the overhead includes using a predetermined number of bits to explicitly indicate each MCS value and each N SS value.

[0027] According to the ninth implementation manner of the first aspect, in an eleventh possible implementation manner of the method, the overhead indicates each MCS and N to be used by indicating a corresponding entry in a predefined table that lists some or all PHY rate indices. SS combination, where each PHY rate index is associated with a unique pair of MCS and N in a predefined manner SS Value associated.

[0028] According to the ninth implementation manner of the first aspect, in a twelfth possible implementation manner of the method, for a single N SS The overhead includes an indication of the used value of the MCS and an order of the used values ​​of the MCS.

[0029] According to the ninth implementation manner of the first aspect, in a thirteenth possible implementation manner of the method, the overhead further includes a predefined table, wherein the predefined table uses a field with a predefined number of bits to indicate the modulation codeword and its corresponding MCS and N SS The order of combination.

[0030] According to the first aspect or any one of the first to third implementation manners of the first aspect, in a fourteenth possible implementation manner of the method, the method further includes: creating the modulation codeword to be sent on each frequency subband in one or more of the following manners:

[0031] (i) defining a different predefined bit sequence for each frequency sub-band, and encoding and modulating the different predefined bit sequences to create corresponding different modulation codewords for each frequency sub-band;

[0032] (ii) defining a first predefined bit sequence and further creating different bit sequences for each frequency sub-band by applying different predefined cyclic shifts to the first predefined bit sequence, and further encoding and modulating the different bit sequences to create corresponding different modulation codewords for each frequency sub-band;

[0033] (iii) defining a first predefined bit sequence and further creating different bit sequences for each frequency sub-band by applying different predefined scrambling sequences to the first predefined bit sequence, and further encoding and modulating the different bit sequences to create corresponding different modulation codewords for each frequency sub-band;

[0034] (iv) encoding and modulating the predefined bit sequence into a first modulation codeword comprising a QAM symbol sequence, and further creating different modulation codewords for each frequency subband by applying different predefined permutations to the first QAM symbol sequence, wherein the modulation codewords comprise corresponding different QAM symbol sequences;

[0035] (v) According to MCS and N SS A predefined sequence of combinations, defining a first modulation codeword sequence to be sent on a first frequency subband, and by permuting the MCS and N in the first modulation codeword sequence SS The sequence of combinations further creates different modulation codeword sequences to be transmitted on other frequency sub-bands.

[0036] In the above implementation, it should be understood that in addition to applying different predefined cyclic shifts, other predefined bit permutations may also be applied. For example, a predefined interleaving sequence may be applied to a predefined bit sequence.

[0037] According to the first aspect or the first or second implementation manner of the first aspect, in a fifteenth possible implementation manner of the method, sending a training data packet to the one or more responders also includes: sending a different predefined bit sequence to each responder or sending multiple different predefined bit sequences to the same responder in each training data packet.

[0038] According to the first aspect, in a sixteenth possible implementation of the method, the adjusted transmission scheme parameters of the subsequent data packets include one or more of the following: modulation and coding scheme (MCS); number of spatial streams N SS ; allocated frequency sub-bands.

[0039] Therefore, the present invention provides for the use of multiple MCS and possibly multiple N in the same PPDU. SS The technical solution for sending codewords using values ​​and indicating how codewords should be generated and how subcarrier mapping should be performed.

[0040] The present invention also provides a second aspect of a method for performing link adaptation in a wireless communication network. The wireless communication network includes at least one initiator and one or more responders, and the method includes: the one or more responders receive a training data packet including a set of predefined bit sequences from the initiator, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCS), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; the one or more responders send a feedback report of each of the responders to the initiator, wherein the feedback report includes a value of a measured link performance indicator related to each modulation codeword received by the corresponding responder from the initiator.

[0041] According to the second aspect, in a first possible implementation of the method, the wireless communication network is a wireless local access network (WLAN); the initiator and the responder are WLAN devices; the data packet is a physical protocol data unit (PPDU); and the predefined frequency subband is a resource unit (RU).

[0042] According to the second aspect or any of the above implementations of the second aspect, in a second possible implementation, at least two of the modulation codewords included in the training data packet are respectively transmitted by different numbers N SS spatial stream to receive.

[0043] According to the second aspect or any of the above implementations of the second aspect, in a third possible implementation, the one or more responders receiving a training data packet also includes: each responder receiving a different modulation codeword or the same responder receiving multiple different codewords in each training data packet.

[0044] According to the second implementation manner of the second aspect, in a fourth possible implementation manner, receiving the training data packet includes: each responder receiving a different modulation codeword from the initiator or the same responder receiving multiple different modulation codewords in each training data packet.

[0045] The present invention also provides a third aspect of an apparatus in a wireless communication network. The network includes one or more responders, and the apparatus includes at least one initiator, the initiator being used to: send a training data packet including a set of predefined bit sequences to the one or more responders, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCS), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; receive feedback reports from each of the responders, wherein the feedback reports include values ​​of measured link performance indicators related to each modulation codeword sent to the corresponding responder; and adjust transmission scheme parameters of subsequent data packets on the communication link between the initiator and the one or more responders based on the reported feedback.

[0046] According to the third aspect, in a first possible implementation of the device, the wireless communication network is a wireless local access network (WLAN); the initiator and the responder are WLAN devices; the data packet is a physical protocol data unit (PPDU); and the predefined frequency subband is a resource unit (RU).

[0047] According to the third aspect or any of the above implementations of the third aspect, in a second possible implementation of the device, the initiator is used to send a training data packet, wherein at least two of the modulation codewords included in the training data packet are respectively transmitted through different numbers N SS The spatial stream is used to send.

[0048] According to the third aspect or any of the above implementations of the third aspect, in a third possible implementation of the device, the initiator is further configured to: encode the predefined bit sequence into a codeword using an LDPC or BCC coding scheme; and allocate the coded bits of each codeword to N SS spatial streams, wherein each corresponding spatial stream carries a bit stream; each bit stream is divided into bit subsequences, wherein each bit subsequence consists of N BPSCS bits, N BPCSS is the number of bits per stream per subcarrier; modulating the bit subsequences comprising each bit stream into a quadrature amplitude modulation (QAM) symbol stream that together constitutes a modulation codeword; dividing the QAM symbols obtained from each QAM symbol stream into a plurality of groups N SS QAM symbols, the initiator being configured to map each group to a single corresponding subcarrier within the frequency subband or RU to which the modulation codeword is mapped.

[0049] According to the third aspect or any of the above implementations of the third aspect, in a fourth possible implementation of the device, the initiator is used to map the modulation codewords to RUs spanning several OFDM symbols in a consecutive order.

[0050] According to the third aspect or any of the above implementations of the third aspect, in a fifth possible implementation of the device, the initiator is used to map the modulation codeword to an RU spanning several OFDM symbols, so that each modulation codeword starts from a different OFDM symbol.

[0051] According to the fourth or fifth implementation of the third aspect, in a sixth possible implementation of the device, the initiator is used to align each modulation codeword in the modulation codeword with the subcarrier, so that the number of bits N per subcarrier per spatial stream carried by each subcarrier in the subcarrier to which the modulation codeword is mapped BPSCS Exactly the same.

[0052] According to the sixth implementation manner of the third aspect, in a seventh possible implementation manner of the device, the initiator is used to align the modulation codeword with the subcarrier, and use any QAM symbol to fill the unused subcarriers of the frequency subband within the used OFDM symbol.

[0053] According to the seventh implementation manner of the third aspect, in an eighth possible implementation manner of the device, the initiator is used to: before modulating the codeword, delete one or more bits at the end of the codeword to align with multiple subcarriers of the OFDM symbol, so that after modulating the codeword, the number of bits N per subcarrier per spatial stream carried by each subcarrier to which the modulated codeword is mapped is BPSCS Exactly the same.

[0054] According to the third aspect or the first or second implementation of the third aspect, in a ninth possible implementation of the device, the initiator is used to send the training data packet and indicate to the responder which modulation codewords and their corresponding MCS and N by including overhead. SS Sent in the training data packet.

[0055] According to the ninth implementation of the third aspect, in a tenth possible implementation of the device, the overhead includes using a predetermined number of bits to explicitly indicate each MCS value and each N SS value.

[0056] According to the ninth implementation manner of the third aspect, in an eleventh possible implementation manner of the device, the overhead indicates each MCS and N to be used by indicating a corresponding entry in a predefined table listing some or all of the PHY rate indexes. SS combination, where each PHY rate index is associated with a unique pair of MCS and N in a predefined manner SS Value associated.

[0057] According to the ninth implementation manner of the third aspect, in a twelfth possible implementation manner of the device, for a single N SS The overhead includes an indication of the used value of the MCS and an order of the used values ​​of the MCS.

[0058] According to the ninth implementation manner of the third aspect, in a thirteenth possible implementation manner of the device, the overhead further includes a predefined table, and the predefined table uses a field with a predefined number of bits to indicate the modulation codeword and its corresponding MCS and N SS The order of combination.

[0059] According to the third aspect or any one of the first to fourth implementations of the device of the third aspect, in a fourteenth possible implementation of the device, the initiator is used to create a payload to be sent on each frequency subband in each OFDM symbol, and the initiator is used to create the modulation codeword to be sent on each frequency subband in one or more of the following ways:

[0060] (i) defining a different predefined bit sequence for each frequency sub-band, and encoding and modulating the different predefined bit sequences to create corresponding different modulation codewords for each frequency sub-band;

[0061] (ii) defining a first predefined bit sequence and further creating different bit sequences for each frequency sub-band by applying different predefined cyclic shifts to the first predefined bit sequence, and further encoding and modulating the different bit sequences to create corresponding different modulation codewords for each frequency sub-band;

[0062] (iii) defining a first predefined bit sequence and further creating different bit sequences for each frequency sub-band by applying different predefined scrambling sequences to the first predefined bit sequence, and further encoding and modulating the different bit sequences to create corresponding different modulation codewords for each frequency sub-band;

[0063] (iv) encoding and modulating the predefined bit sequence into a first modulation codeword comprising a QAM symbol sequence, and further creating different modulation codewords for each frequency subband by applying different predefined permutations to the first QAM symbol sequence, wherein the modulation codewords comprise corresponding different QAM symbol sequences;

[0064] (v) According to MCS and N SS A predefined sequence of combinations, defining a first modulation codeword sequence to be sent on a first frequency subband, and by permuting the MCS and N in the first modulation codeword sequence SS The sequence of combinations further creates different modulation codeword sequences to be transmitted on other frequency sub-bands.

[0065] In the above implementation, it should be understood that in addition to applying different predefined cyclic shifts, other predefined bit permutations may also be applied. For example, a predefined interleaving sequence may be applied to a predefined bit sequence.

[0066] In any one of the first to fifth implementations of the device according to the third aspect or the third aspect, in a fifteenth possible implementation of the device, the initiator is used to send the training data packet to the one or more responders, further comprising: sending a different predefined bit sequence to each responder or sending multiple different predefined bit sequences to the same responder in each training data packet.

[0067] According to the fifteenth implementation of the device of the third aspect, in a sixteenth possible implementation of the device, the adjusted transmission scheme parameters of the subsequent data packets include one or more of the following: modulation and coding scheme (MCS); number of spatial streams N SS ; allocated frequency sub-bands.

[0068] The present invention also provides a fourth aspect of an apparatus in a wireless communication network. The network includes at least one initiator, the apparatus includes one or more responders, and the responders are used to: receive a training data packet including a set of predefined bit sequences from the initiator, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCS), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; send a feedback report of each of the responders to the initiator, wherein the feedback report includes a value of a measured link performance indicator related to each received codeword received by the corresponding responder from the initiator.

[0069] According to the fourth aspect, in a possible implementation of the device, the wireless communication network is a wireless local access network (WLAN); the initiator and the responder are WLAN devices; the data packet is a physical protocol data unit (PPDU); and the predefined frequency subband is a resource unit (RU).

[0070] According to the fourth aspect or any of the above implementations of the fourth aspect, in a possible implementation of the device, at least two of the modulation codewords included in the training data packet are respectively transmitted by different numbers N SS spatial stream to receive.

[0071] The present invention also provides another aspect of a computer program product. The computer program product includes program code, and the program code is used to execute the method according to the first aspect or any of the above implementations of the first aspect, or the method according to the second aspect.

[0072] The present invention also provides another aspect of a non-transitory computer-readable medium carrying program code. When the program code is executed by a computer device, the computer device executes the method according to the first aspect or any of the above implementations of the first aspect, or the method according to the second aspect.

[0073] Any of the above devices may also be referred to as an apparatus. Any of the above devices may be implemented on an integrated chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0075] Figure 1 An example of a wireless communication system is shown in schematic diagram.

[0076] Figure 2 A method for performing link adaptation in a wireless communication network provided by an embodiment of the present invention is shown.

[0077] Figure 3 An example of mapping a training data packet including a set of predefined bit sequences to a pattern on a RU of 10 sub-carriers (SC) and 5 OFDM symbols provided by an embodiment of the present invention is shown.

[0078] Figure 4 An example provided by an embodiment of the present invention is shown in which an assumed RU has 10 SCs and a 22-bit CW.

[0079] Figure 5 Another embodiment of the present invention provides a possible MCS and N SS A predefined table of value combinations and their associated PHY rate index.

[0080] Figure 6 A list of predefined schemes under a two-bit index of a single spatial stream and an MCS sorting scheme provided by another scheme of yet another embodiment of the present invention is shown.

[0081] Figure 7 FIG. 1 shows a codeword MCS and N using a two-bit index provided by another embodiment of the present invention. SS An example of a predefined order of combinations.

[0082] Figure 8 Another embodiment of the present invention provides a method for performing link adaptation in a wireless communication network.

[0083] Fig. 9 Another embodiment according to the present invention is shown, which includes an apparatus in a wireless communication network.

[0084] Fig.10 According to another embodiment of the present invention, a device in a wireless communication network is shown. DETAILED DESCRIPTION

[0085] In the following description, reference is made to the accompanying drawings that form a part of the present invention, which illustrate by way of illustration specific aspects of embodiments of the present invention or specific aspects in which embodiments of the present invention may be used. It should be understood that embodiments of the present invention may be used in other aspects and may include structural changes or logical changes not depicted in the accompanying drawings. Therefore, the following detailed description should not be understood in a restrictive sense, and the scope of the present invention is defined by the appended claims.

[0086] For example, it is understood that the disclosure related to describing a method may also be applicable to a 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 described one or more method steps (e.g., one unit performs one or more steps, or multiple units perform one or more steps of multiple steps respectively), even if such one or more units are not explicitly described or illustrated in the drawings. On the other hand, for example, if a specific device is described based on one or more units (e.g., functional units), the corresponding method may include a step to perform the function of one or more units (e.g., one step performs the function of one or more units, or multiple steps perform the function of one or more units of multiple units respectively), even if such one or more steps are not explicitly described or illustrated in the drawings. In addition, it is understood that, unless otherwise explicitly stated, the features of the various exemplary embodiments and / or aspects described herein may be combined with each other.

[0087] Figure 1An example of a wireless communication system 100 is shown. The communication system 100 includes an access point (AP) 105, which serves one or more stations (STAs) 110, 112, 114, 116, and 118. Within the meaning of the present invention, an AP may also be referred to as an initiator, for example, an initiator of a particular request. Similarly, one or more STAs may also be referred to as one or more responders. The AP 105 typically controls various aspects of communicating with its associated stations or between its associated stations, such as radio frequency channels, transmission power limits, authentication, and security. In some cases, in the communication system 100, a transmitter may access wireless resources for uplink transmission (i.e., a link from a STA to an AP) and downlink transmission (i.e., a link from an AP to a STA) based on a distributed contention mechanism generally referred to as carrier sensing multiple access with collision avoidance (CSMA / CA). In some examples, AP is called 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., and STA can also generally be called user equipment (UE), mobile station, mobile phone, terminal, user, subscriber, site, etc. The AP may provide wireless access based on 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. Although it is understood that the communication system may use multiple APs capable of communicating with multiple sites, for simplicity, Figure 1Only one AP 105 and five stations 110 to 118 are shown.

[0088] 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 wireless networks compliant with IEEE 802.11, 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 input to a generator, which generates coded bits. Each consecutive subset of coded bits is a function of the information bits currently residing in the generator's buffer, which is typically about 6 bits in size. In the case of LDPC coding, several codeword sizes are defined. The information bits are divided into independent non-overlapping parts. These parts are encoded separately. To align with the predefined LDPC codeword size, the information bits can be padded using shortening bits, pre-forward error correction (FEC) padding, or can be fully or partially repeated.

[0089] Example 1

[0090] According to a first embodiment of the present invention, codewords (CW) are modulated continuously, i.e., modulated one codeword after another in frequency and time. Here, several CWs may also be used for each MCS, for example, for a higher MCS, more CWs may be used, each CW occupying fewer subcarriers.

[0091] Figure 2 A method for performing link adaptation in a wireless communication network provided by the present invention is shown. The method for performing link adaptation in a wireless communication network involves at least one initiator and one or more responders. The method comprises the following steps:

[0092] Step 251: The initiator sends a training data packet including a set of predefined bit sequences to the one or more responders, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCS), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; Step 253: The initiator receives a feedback report from each of the responders, wherein the feedback report includes the value of a measured link performance indicator related to each codeword sent to the corresponding responder; Step 255: Based on the reported feedback, adjust the transmission scheme parameters of subsequent data packets on the communication link between the initiator and the one or more responders.

[0093] Therefore, in this embodiment, the CW is usually generated without shortening or repetition. However, shortening or repetition may be required as described below. Figure 3 An example of a training data packet including a set of predefined bit sequences is shown. The predefined bit sequences are encoded into 22-bit codewords, which are modulated using one or more MCS values. The modulated CW is mapped onto predefined subbands. Figure 3 In , it is assumed that an RU with 10 subcarriers, spanning 5 OFDM symbols, and a single spatial stream is used. In other words, Figure 3 The mapping pattern of a continuous 22-bit modulated CW mapped onto a RU with 10 subcarriers is shown. It should be understood here that the selection of 10 subcarriers and 22-bit CW is only for illustration purposes, and a different number of subcarriers and a different number of bits in the CW and a different number of CWs can also be selected. There are two schemes to align the CW with the subcarriers so that each subcarrier uses exactly the specified number of bits per subcarrier per stream, i.e., N BPSCS bits, where N BPSCS is an integer greater than zero:

[0094] Do not puncture the symbols, but pad a few bits at the end of the last symbol; or

[0095] Puncture a few bits at the end of the last symbol.

[0096] The proposed CW mapping is performed before low-density parity-check (LDPC) subcarrier mapping, ie before interleaving a quadrature amplitude modulation (QAM) symbol sequence (or simply QAM sequence).

[0097] In more detail, Figure 3The example in shows a RU with 10 subcarriers (SCs) (subcarrier / tone) and 5 OFDM symbols, here RU_0. Figure 3 It shows the encoding and modulation of a predefined bit sequence using modulation and coding schemes MCS 0, MCS1, MCS3, MCS 5, MCS 8, and MCS10. There are 22 QAMs corresponding to the first modulation CW using MCS 0, i.e., MCS0_0, MCS0_1 …… MCS0_21, which occupy OFDM symbol 0 (SCs 0 to SC9), OFDM symbol 1 (SCs 0 to SC 9), and OFDM symbol 2 (SCs 0 and SC 1) in sequence. Followed by the QAMs of the second modulation CW using MCS1, i.e., MCS1_0 …… MCS1_10, starting from OFDM symbol 2 (SCs 2 to SC 9) and OFDM symbol 3 (SCs 0 to SC 2). Followed by the QAMs of MCS 3, i.e., MCS3_0 …… MCS3_5, starting from OFDM symbol 3 (SCs 3 to SC 8). Followed by the QAMs of MCS5, i.e., MCS5_0 …… MCS5_3, starting from OFDM symbol 3 (SC 9) and continuing to OFDM symbol 4 (SCs 0 to SC 2). Followed by the QAMs of MCS 8, starting from OFDM symbol 4 (SCs 3 to SC 5). Followed by the QAMs of the sixth (and the last in this example) modulation CW using MCS10, starting from OFDM symbol 4 (SCs 6 to SC 8). The subcarriers of OFDM symbol 4 (SC 9) are filled. In this example, MCS 0 and MCS1 include 0 padding bits; MCS 3, MCS 5, and MCS 8 each include 2 padding bits; MCS10 includes 8 padding bits.

[0098] It should be understood that different Ns SS can be used to transmit each CW or multiple CWs constructed by different MCSs: For this, the initiator needs to modify the power of each subcarrier of each stream so that the total power of each OFDM symbol remains constant regardless of how the number of spatial streams N SS varies.

[0099] In addition, the number of long training fields (LTFs), especially the number of extremely high throughput long training fields (EHT-LTFs), will reflect the maximum number of streams. Therefore, in the time-frequency region where the number of streams in the training frame is less than the maximum N SS the receiver needs to consider the difference in power of each stream relative to the (EHT)-LTF.

[0100] Example 2

[0101] and Figure 2 and Figure 3 In contrast, in a similar setting, another embodiment of the present invention discloses that each modulation codeword (CW) starts from a different OFDM symbol. Here, several CWs can also be used for each MCS, for example, more CWs can be used for a higher MCS. In this embodiment, the CW is generated in a shortened or repeated manner.

[0102] Figure 4 An example is shown assuming that the RU has 10 subcarriers and a 22-bit CW. Again, it should be understood that the selection of 10 subcarriers and 22-bit CW is for illustration purposes only, and a different number of subcarriers and a different number of bits in the CW may also be selected. In this embodiment, there are two schemes for aligning the CW with the subcarriers so that each subcarrier uses exactly a specified number of bits per subcarrier per stream, i.e., N BPSCS bits, where N BPSCS is an integer greater than zero:

[0103] Do not puncture the symbols; instead, pad a few bits at the end of the corresponding OFDM symbol; or

[0104] • Puncture a few bits at the end of the corresponding OFDM symbol.

[0105] Different numbers of spatial streams (i.e. different N SS value) to send each CW constructed with a certain MCS.

[0106] In more detail, Figure 4 The example in FIG. 1 shows an RU, here RU_0, with 10 subcarriers (subcarrier / tone) and 8 OFDM symbols. Figure 3 The example shown is similar to, Figure 4 The example in shows the case of using modulation coding schemes MCS0, MCS 1, MCS 3, MCS 5, MCS 8, MCS10. Figure 4In the example, when MCS 0 is used, a single modulation CW includes 22 QAMs, namely MCS0_0, MCS0_1...MCS0_21, which occupy symbol 0 (SC 0 to SC 9), symbol 1 (SC0 to SC 9) and symbol 2 (SC 0 and SC 1) in sequence. The QAM of MCS1, namely MCS1_0...MCS1_10, starts from the symbol immediately following symbol 2. Here, in this example, this symbol is symbol 3, namely symbol 3 (SC 0 to SC 9), followed by symbol 4 (SC0). The rest of symbol 4 can be padded or filled with additional punctured CWs. The QAM of MCS 3, namely MCS3_0...MCS3_5, starts from the symbol immediately following symbol 4. Here, in this example, this symbol is symbol 5 (SC 0 to SC5). The rest of symbol 5 can be padded or filled with additional punctured CWs. Figure 4 In the example of , two CWs using MCS 5 are sent, wherein the QAM corresponding to the second CW is further indicated by the suffix "b". The QAM of MCS 5, i.e., MCS5_0...MCS5_3, MCS5_0b, MCS5_1b, MCS5_2b, MCS5_3b, starts from the symbol immediately following symbol 5. Here, in this example, this symbol is symbol 6 (SC 0 to SC 7). The rest of symbol 6 can be filled. The QAM of three CWs using MCS8, i.e., MCS8_0, MCS8_1, MCS8_2, MCS8_0b, MCS8_1b, MCS8_2b, MCS8_0c, MCS8_1c, MCS8_2c, starts from the symbol immediately following symbol 6. Here, in this example, this symbol is symbol 7 (SC 0 to SC 8). The rest of symbol 7 can be filled. QAM of four CWs using MCS 10, i.e., MCS10_0 ... MCS10_2, MCS10_1b, MCS_10_2b, MCS10_1c, MCS10_2c, MCS10_1d_MCS10_2d, starts from the symbol immediately following symbol 7. Here, in this example, this symbol is symbol 8 (SC 0 to SC 8). The rest of symbol 8 can be filled.

[0107] Therefore, in this embodiment, an example of using 22 coded bits per CW has been shown. MCS 0 and MCS 1 have 0 padding bits. MCS 3 has 2 padding bits. MCS 5 has 2 CWs and 4 padding bits. MCS 8 has 3 CWs and 6 padding bits. MCS10 has 4 CWs and 2 padding bits.

[0108] Unlike Example 1, Example 2 avoids the problem of the power of each stream constantly changing between different subcarriers in the same OFDM symbol. In addition, in Example 2, the number of (EHT-)LTFs reflects the maximum number of streams. Therefore, when the number of streams is less than the maximum N SS OFDM symbols, the receiver has to take into account the power differences.

[0109] Example 3

[0110] In another embodiment of the present invention, a binary convolutional code (BCC) is used instead of LDPC. Here, a "BCC block" of a predefined length can be used, for example, a block of 1944 bits. It should be noted that BCC does not operate on information bit blocks like LDPC. In this embodiment, similar to Embodiment 2, each MCS and N SS The combined one or more "BCC blocks" will be mapped to a single OFDM symbol.

[0111] An alternative design of Embodiment 3 is to use SS The codeword encoded using BCC is sent on a predefined number of OFDM symbols combined.

[0112] Example 4

[0113] In yet another embodiment according to the present invention, the training data is sent by including an overhead to indicate to the responder which code words (CW) and their corresponding MCS and N SS In this way, the CW and its corresponding MCS and N are also sent. SS For the overhead, you can choose the following schemes:

[0114] Solution 1: According to the first solution of this embodiment, the overhead may include using a predetermined number of bits to explicitly indicate each MCS value and N SS This can be achieved through the extremely high throughput signal field EHT-SIG / LA-SIG. Specifically, 4 bits can be used to indicate each MCS value, and 2 bits or 3 bits can be used to indicate the number of spatial streams N. SS It will be appreciated that a different number of bits may also be used.

[0115] Solution 2: According to the second solution of this embodiment, the overhead may indicate each MCS and N to be used by indicating the corresponding entry in the predefined table. SSThe predefined table may list some or all PHY rate indexes, wherein each PHY rate index is associated with a unique pair of MCS and N in a predefined manner. SS Specifically, the table can arrange all MCS and N values ​​in ascending order according to the PHY throughput. SS Combinations, for example, require 16*8=128 combinations, and an index may indicate each combination in the table, for example, each index uses 7 bits.

[0116] Figure 5 With 128 possible MCS and N SS The second solution is shown as an example of 10 combinations in the combination. Figure 5 A table is shown with 10 columns indexed by 0, 1, ..., 9, indicating possible MCS and N SS Combination, indicating the number of bits per subcarrier for each of the 10 combinations. Figure 5 The MCS values ​​in the table shown follow the conventions of the IEEE 802.11 WLAN standard, and each value represents a specific modulation type and coding rate.

[0117] Solution 3: According to the third solution of this embodiment, the table described in the second solution can be further shortened to include only Figure 5 A subset of the combinations shown, but omitting impractical combinations, e.g., MCS 0 and N in the table SS = 2. Therefore, the table may be much shorter than the table of Scheme 2; for example, the table may include only 32 combinations instead of 128 combinations.

[0118] Solution 4: According to the fourth solution of this embodiment, for a single N SS The overhead may include an indication of the used value of the MCS and the order in which the used values ​​of the MCS are used. In other words, according to this scheme, the overhead may include an index to one of a list of predefined schemes. SS Value, indicating the MCS value and the order of the MCS.

[0119] Figure 6 It shows that N SS = An example of a list of predefined schemes with 1 and 2 bit indices, i.e., four schemes in total. SS =1 value and 7 MCSs, according to the indicated 2-bit scheme index, the index and usage value of the MCS can be found in the table.

[0120] Solution 5: According to the fifth solution of this embodiment, the overhead may include an index pointing to a specific entry in a predefined table, where the specific entry indicates the modulation codeword and its corresponding MCS and N using a field with a predefined number of bits.SS In other words, the overhead may include a pointer to an entry in a predefined table that specifies the CW with the MCS and N SS The order of combination.

[0121] Figure 7 shows CW with seven MCS and N SS An example of a predefined list of possible sequences of combinations, using a 2-bit index, is four options in total. Figure 7 In the table, the columns in the table indicate value #1 to value #7, which are the corresponding MCS and N used by the indicated scheme. SS The order of these combinations is indexed by 0, 1, 2 or 3, and the indication scheme is selected from the four options shown in each row.

[0122] Example 5

[0123] In yet another embodiment according to the present invention, the initiator is expected to send LA training frames, ie, known codewords, in several RUs (eg, in each 242-tone RU).

[0124] The reason for this is that the expected link performance of a wider BW (e.g., 996-tone RU) can be inferred from the expected link performance of several narrower BW portions (e.g., four 242-tone RUs). However, the reverse is not true.

[0125] One solution is to keep the content of each RU in the LA training frame basically unchanged, regardless of the position of the RU in the frequency. This may simplify the feedback information reported by the responder and make the feedback information of each RU have the same meaning or format.

[0126] However, sending the same replicated frequency domain signal in multiple RUs may cause time duplication within the OFDM symbol and may produce an excessively high peak to average power ratio (PAPR), so remedial measures need to be taken.

[0127] Several different technical solutions to solve this problem according to this embodiment are listed below:

[0128] Technical Solution #1: Define different predefined bit sequences in each OFDM symbol to be used as payload to be sent on each RU.

[0129] Technical Solution #2: Define a single predefined bit sequence, and generate different predefined bit sequences for each RU according to the predefined bit sequence by applying different predefined cyclic shifts or some other predefined permutations to the predefined bit sequence, for example, applying a predefined interleaving sequence to the predefined bit sequence

[0130] Technical Solution #3: Similar to Technical Solution #2, but the different cyclic shifts applied are replaced by different scrambling sequences, which may be defined by different random numbers (seeds) of some kind of Linear Feedback Shift Register (LFSR) (e.g., the same LFSR already defined by the IEEE 802.11 WLAN standard for other purposes).

[0131] • Technical Solution #4: Apply different predefined cyclic shifts or some other predefined permutations to the modulation QAM before or after LDPC subcarrier mapping.

[0132] Technical Solution #5: Change the MCS and N of each RU SS The order of the combination; for example, if the order of the MCS values ​​in the first RU is 0, 1, 2, 3, then the order in the second RU is 1, 2, 3, 0.

[0133] Example 6

[0134] In another embodiment according to the present invention, the initiator may choose to use multiple potential codewords to send, and thus may indicate to one or more responders which codeword to use in the LA transmission. The initiator may choose to send a different codeword to each responder, or may send a different codeword to the same responder in each training PPDU.

[0135] According to yet another embodiment of the present invention, Figure 8A method for performing link adaptation in a wireless communication network provided by the present invention is shown. The method for performing link adaptation in a wireless communication network involves at least one initiator and one or more responders. The method comprises the following steps: Step 351: the one or more responders receive a training data packet including a set of predefined bit sequences from the initiator, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCS), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; Step 353: the one or more responders send a feedback report of each of the responders to the initiator, wherein the feedback report includes a value of a measured link performance indicator related to each modulation codeword received by the corresponding responder from the initiator.

[0136] Fig. 9 Another embodiment provided by the present invention is shown. Fig. 9 An apparatus 20 in a wireless communication network is shown, the network includes one or more responders, the apparatus includes at least one initiator, the initiator includes:

[0137] A sending unit 2501 is used to send a training data packet including a set of predefined bit sequences to the one or more responders, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCS), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; a receiving unit 2503 is used to receive a feedback report from each of the responders, wherein the feedback report includes a value of a measured link performance indicator related to each modulation codeword sent to the corresponding responder; an adjustment unit 2505 is used to adjust a transmission scheme parameter of a subsequent data packet on the communication link between the initiator and the one or more responders based on the reported feedback.

[0138] Fig.10 Another embodiment provided by the present invention is shown. Fig.10A device in a wireless communication network is shown, the network includes at least one initiator, the device includes at least one responder, the responder includes: a receiving unit 3501, used to receive and calculate the link performance indicator from the initiator, wherein the link performance indicator is related to the one or more received codewords included in a training data packet, the training data packet includes a set of predefined bit sequences, the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCS), each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subband has a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; a sending unit 3502, used to send a feedback report of the responder to the initiator, wherein the feedback report includes the value of the measured link performance indicator related to each received codeword received from the initiator.

[0139] In summary, as mentioned above, since the convergence speed of practical and popular link adaptation mechanisms such as Minstrel is very slow, the technical solution proposed by the present invention here will greatly accelerate the convergence speed of the LA process and improve the system efficiency.

Claims

1. A method for performing link adaptation in a wireless communication network, wherein the wireless communication network comprises at least one initiator and one or more responders, wherein the method include: The initiator sends a training data packet including a set of predefined bit sequences to the one or more responders, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCSs), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; The initiator receives a feedback report from each of the responders, wherein the feedback report includes a value of a measured link performance indicator associated with each codeword sent to the corresponding responder; According to the reported feedback, transmission scheme parameters of subsequent data packets are adjusted on the communication link between the initiator and the one or more responders.

2. The method according to claim 1, Features: The wireless communication network is a wireless local access network WLAN; The initiator and the responder are WLAN devices; The data packet is a physical protocol data unit PPDU; The predefined frequency subband is a resource unit RU.

3. The method according to claim 1 or 2, It is characterized in that At least two of the modulation codewords included in the training data packet are respectively transmitted through different numbers N SS The spatial stream is used to send.

4. The method according to any one of claims 1 to 3, further comprising: include: Encode the predefined bit sequence into codewords by LDPC or BCC coding scheme respectively; distribute the coded bits including each codeword to N SS spatial streams, wherein each corresponding spatial stream carries a bit stream; each bit stream is further divided into bit subsequences, wherein each bit subsequence consists of N BPSC bits, N BPSC is the number of bits per stream per subcarrier; further modulating the bit subsequences comprising each bit stream into a quadrature amplitude modulation QAM symbol stream that together constitutes a modulation codeword; dividing the QAM symbols obtained from each QAM symbol stream into a plurality of groups N SS QAM symbols, wherein each group is mapped to a single corresponding subcarrier within the frequency subband to which the modulation codeword is mapped.

5. The method according to any one of claims 1 to 4, It is characterized in that The modulation codewords are mapped onto the OFDM symbols in a consecutive order.

6. The method according to any one of claims 1 to 5, It is characterized in that The modulation codewords are mapped onto the OFDM symbols such that each modulation codeword starts from a different OFDM symbol.

7. The method according to claim 5 or 6, It is characterized in that Each modulation codeword in the modulation codeword is aligned with the subcarrier so that the number of bits per subcarrier per spatial stream carried by each subcarrier to which the modulation codeword is mapped is N BPSCS Exactly the same.

8. The method according to claim 7, It is characterized in that Aligning the modulation codewords with the subcarriers includes filling unused subcarriers of the frequency subband within the used OFDM symbols.

9. The method according to claim 5 or 6, It is characterized in that Before modulating the codeword, one or more bits at the end of the codeword are deleted to align with multiple subcarriers of the OFDM symbol, so that after modulating the codeword, the number of bits per subcarrier per spatial stream carried by each subcarrier to which the modulated codeword is mapped is N BPSCS Exactly the same.

10. The method according to any one of claims 1 to 3, It is characterized in that The sending of the training data packet includes: indicating to the responder which modulation code words and their corresponding MCS and N by including overhead Ss Sent in the training data packet.

11. The method according to claim 10, It is characterized in that The overhead includes using a predetermined number of bits to explicitly indicate each MCS and each N SS .

12. The method according to claim 10, It is characterized in that The overhead indicates each MCS and N to be used by indicating a corresponding entry in a predefined table listing some or all of the PHY rate indices. SS combination, where each PHY rate index is associated with a unique pair of MCS and N in a predefined manner SS Value associated.

13. The method according to claim 10, It is characterized in that For a single N SS The overhead includes an indication of the used value of the MCS and an order of the used values ​​of the MCS.

14. The method according to claim 10, It is characterized in that The overhead also includes a predefined table that uses a field with a predefined number of bits to indicate the modulation codeword and its corresponding MCS and N SS The order of combination.

15. The method according to any one of claims 1 to 4, further comprising: include: The modulation codeword is created to be sent on each frequency subband by one or more of the following methods: (i) defining a different predefined bit sequence for each frequency sub-band, and encoding and modulating the different predefined bit sequences to create corresponding different modulation codewords for each frequency sub-band; (ii) defining a first predefined bit sequence and further creating different bit sequences for each frequency sub-band by applying different predefined cyclic shifts to the first predefined bit sequence, and further encoding and modulating the different bit sequences to create corresponding different modulation codewords for each frequency sub-band; (iii) defining a first predefined bit sequence and further creating different bit sequences for each frequency sub-band by applying different predefined scrambling sequences to the first predefined bit sequence, and further encoding and modulating the different bit sequences to create corresponding different modulation codewords for each frequency sub-band; (iv) encoding and modulating the predefined bit sequence into a first modulation codeword comprising a QAM symbol sequence, and further creating different modulation codewords for each frequency subband by applying different predefined permutations to the first QAM symbol sequence, wherein the modulation codewords comprise corresponding different QAM symbol sequences; (v) According to MCS and N SS A predefined sequence of combinations, defining a first modulation codeword sequence to be sent on a first frequency subband, and by permuting the MCS and N in the first modulation codeword sequence SS The sequence of combinations further creates different modulation codeword sequences to be transmitted on other frequency sub-bands.

16. The method according to any one of claims 1 to 3, It is characterized in that The sending of the training data packet to the one or more responders further includes: sending a different predefined bit sequence to each responder or sending a plurality of different predefined bit sequences to the same responder in each training data packet.

17. The method according to claim 1, It is characterized in that The adjusted transmission scheme parameters of the subsequent data packets include one or more of the following: Modulation Coding Scheme MCS; Number of spatial streams N SS ; Allocated frequency sub-bands.

18. A method for performing link adaptation in a wireless communication network, the wireless communication network comprising at least one initiator and one or more responders, the method include: The one or more responders receive a training data packet including a set of predefined bit sequences from the initiator, wherein the predefined bit sequences are encoded into codewords, the codewords are modulated using one or more modulation and coding schemes (MCSs), and each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subbands have a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; The one or more responders send a feedback report of each of the responders to the initiator, wherein the feedback report includes a value of a measured link performance indicator associated with each modulation codeword received by the corresponding responder from the initiator.

19. The method according to claim 18, Features: The wireless communication network is a wireless local access network WLAN; The initiator and the responder are WLAN devices; The data packet is a physical protocol data unit PPDU; The predefined frequency subband is a resource unit RU.

20. The method according to claim 18 or 19, It is characterized in that At least two of the modulation codewords included in the training data packet are respectively transmitted through different numbers N SS spatial stream to receive.

21. The method according to any one of claims 18 to 20, It is characterized in that The one or more responders receiving the training data packet further includes: each responder receiving a different modulation codeword or the same responder receiving a plurality of different codewords in each training data packet.

22. The method according to claim 20, It is characterized in that The receiving of the training data packet includes: each responder receiving a different modulation code word from the initiator or the same responder receiving a plurality of different modulation code words in each training data packet.

23. An apparatus (20) in a wireless communication network, the network comprising one or more responders, the apparatus (20) comprising at least one initiator, The initiator is used to: sending a training data packet including a set of predefined bit sequences to the one or more responders, in, The predefined bit sequence is encoded into a codeword, the codeword is modulated using one or more modulation and coding schemes (MCS), each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subband has a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; receiving a feedback report from each of the responders, wherein the feedback report includes a value of a measured link performance indicator associated with each modulation codeword sent to the corresponding responder; According to the reported feedback, transmission scheme parameters of subsequent data packets are adjusted on the communication link between the initiator and the one or more responders.

24. The device according to claim 23, Features: The wireless communication network is a wireless local access network WLAN; The initiator and the responder are WLAN devices; The data packet is a physical protocol data unit PPDU; The predefined frequency subband is a resource unit RU.

25. The device according to claim 23 or 24, It is characterized in that The initiator is used to respectively pass different numbers N SS At least two of the modulation codewords included in the training data packet are sent through a spatial stream.

26. The device according to any one of claims 23 to 25, It is characterized in that The initiator is also used to: The predefined bit sequence is encoded into codewords by LDPC or BCC coding scheme, and the coded bits comprising each codeword are allocated to N SS spatial streams, wherein each corresponding spatial stream carries a bit stream; Each bit stream is divided into bit subsequences, where each bit subsequence consists of N BPSCS bits, N BPSCS is the number of bits per stream per subcarrier, modulating the bit subsequences comprising each bit stream into a quadrature amplitude modulation (QAM) symbol stream that together constitutes a modulation codeword; The QAM symbols obtained from each QAM symbol stream are divided into multiple groups N SS QAM symbols, The initiator is configured to map each group to a single corresponding subcarrier within the frequency subband to which the modulation codeword is mapped.

27. The device according to any one of claims 23 to 26, It is characterized in that The initiator is used to map the modulation codewords onto the OFDM symbols in a continuous order.

28. The device according to any one of claims 23 to 27, It is characterized in that The initiator is used to map the modulation codewords to the OFDM symbols so that each modulation codeword starts from a different OFDM symbol.

29. The device according to claim 27 or 28, It is characterized in that The initiator is used to align each modulation codeword in the modulation codeword with the subcarrier, so that the number of bits per subcarrier per spatial stream carried by each subcarrier in the subcarrier to which the modulation codeword is mapped is N BPSCS Exactly the same.

30. The device according to claim 29, It is characterized in that The initiator is used to align the modulation codeword with the subcarrier and fill unused subcarriers of the frequency subband within the used OFDM symbol.

31. The device according to claim 30, It is characterized in that The initiator is used to: before modulating the codeword, delete one or more bits at the end of the codeword to align with multiple subcarriers of the OFDM symbol, so that after modulating the codeword, the number of bits N per subcarrier per spatial stream carried by each subcarrier to which the modulated codeword is mapped is BPSCS Exactly the same.

32. The device according to any one of claims 23 to 25, It is characterized in that The initiator is used to send the training data packet and indicate to the responder which modulation codewords and their corresponding MCS and N by including overhead SS Sent in the training data packet.

33. The device according to claim 32, It is characterized in that The overhead includes using a predetermined number of bits to explicitly indicate each MCS and each N SS .

34. The device according to claim 32, It is characterized in that The overhead indicates each MCS and N to be used by indicating a corresponding entry in a predefined table listing some or all of the PHY rate indices. fS combination, where each PHY rate index is associated with a unique pair of MCS and N in a predefined manner SS Value associated.

35. The device according to claim 32, It is characterized in that For a single N SS The overhead includes an indication of the used value of the MCS and an order of the used values ​​of the MCS.

36. The device according to claim 32, It is characterized in that The overhead also includes a predefined table that uses a field with a predefined number of bits to indicate the modulation codeword and its corresponding MCS and N SS The order of combination.

37. The device according to any one of claims 23 to 27, It is characterized in that The initiator is used to create a payload to be sent on each frequency subband in each OFDM symbol, and the initiator is used to create the modulation codeword to be sent on each frequency subband in one or more of the following ways: (i) defining a different predefined bit sequence for each frequency sub-band, and encoding and modulating the different predefined bit sequences to create corresponding different modulation codewords for each frequency sub-band; (ii) defining a first predefined bit sequence and further creating different bit sequences for each frequency sub-band by applying different predefined cyclic shifts to the first predefined bit sequence, and further encoding and modulating the different bit sequences to create corresponding different modulation codewords for each frequency sub-band; (iii) defining a first predefined bit sequence and further creating different bit sequences for each frequency sub-band by applying different predefined scrambling sequences to the first predefined bit sequence, and further encoding and modulating the different bit sequences to create corresponding different modulation codewords for each frequency sub-band; (iv) encoding and modulating the predefined bit sequence into a first modulation codeword comprising a QAM symbol sequence, and further creating different modulation codewords for each frequency subband by applying different predefined permutations to the first QAM symbol sequence, wherein the modulation codewords comprise corresponding different QAM symbol sequences; (v) According to MCS and N SS A predefined sequence of combinations, defining a first modulation codeword sequence to be sent on a first frequency subband, and by permuting the MCS and N in the first modulation codeword sequence SS The sequence of combinations further creates different modulation codeword sequences to be transmitted on other frequency sub-bands.

38. The device according to any one of claims 23 to 26, It is characterized in that The initiator sending the training data packet to the one or more responders further includes: sending a different predefined bit sequence to each responder or sending multiple different predefined bit sequences to the same responder in each training data packet.

39. The device according to claim 26, It is characterized in that The adjusted transmission scheme parameters of the subsequent data packets include one or more of the following: Modulation Coding Scheme MCS; Number of spatial streams N SS ; Allocated frequency sub-bands.

40. An apparatus (30) in a wireless communication network, the network comprising at least one initiator, the apparatus comprising at least one responder, the responder being configured to: receiving a training data packet including a set of predefined bit sequences from the initiator, in, The predefined bit sequence is encoded into a codeword, the codeword is modulated using one or more modulation and coding schemes (MCS), each modulation codeword is mapped to one or more predefined frequency subbands in a predetermined manner, the frequency subband has a predefined number of subcarriers, and the subcarriers span one or more orthogonal frequency division multiplexing (OFDM) symbols; A feedback report of each of the responders is sent to the initiator, wherein the feedback report includes a value of a measured link performance indicator associated with each received codeword received by the corresponding responder from the initiator.

41. The device according to claim 40, Features: The wireless communication network is a wireless local access network WLAN; The initiator and the responder are WLAN devices; The data packet is a physical protocol data unit PPDU; The predefined frequency subband is a resource unit RU.

42. The device according to claim 40 or 41, It is characterized in that At least two of the modulation codewords included in the training data packet are respectively transmitted through different numbers N SS spatial stream to receive.

43. A computer program product comprising a program code for executing the method according to any one of the preceding claims 1 to 18 when the program code is executed on a computer or a processor.

44. A non-transitory computer readable medium carrying program code, which, when executed by a computer device, causes the computer device to perform the method according to any one of claims 1 to 18.

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