Modulation and coding scheme selection method and apparatus, terminal and storage medium

Abstract

The embodiments of the present invention relate to the technical field of wireless communications, and disclose a modulation and coding scheme selection method and apparatus, a terminal and a storage medium. In the present invention, when the distance to an access point exceeds a preset distance, some features in a modulation and coding scheme table are restricted, for example, some rows in the modulation and coding scheme table are restricted, and / or the number of spatial streams is restricted. After a first modulation and coding scheme index is obtained by selecting modulation and coding scheme indexes in the modulation and coding scheme table of which some features are restricted, a modulation and coding scheme index offset is used to amend the first modulation and coding scheme index to a second modulation and coding scheme index. Thus, in the case of long-distance transmission, the present invention not only satisfies the transmission demand for a gradually increasing data volume, but also ensures that the data transmission rate is not reduced due to the effect of long distance while ensuring wide enough coverage.

Description

Modulation and coding strategy selection methods, devices, terminals and storage media Cross-references to related applications

[0001] This application is based on and claims priority to Chinese Patent Application No. CN202410803579.9, filed on June 20, 2024, the entire contents of which are hereby incorporated herein by reference. Technical Field

[0002] This application relates to the field of wireless communication technology, and in particular to a modulation and coding strategy selection method, apparatus, terminal, and storage medium. Background Technology

[0003] To meet diverse application scenarios and support various services and applications, wireless Fidelity (Wi-Fi) technology has continuously evolved. To improve throughput, Wi-Fi supports multiple modulation and coding methods, while spatial streams, antenna count, and bandwidth have also been gradually enhanced. The frequency unit for bandwidth used in Wi-Fi data transmission is hertz (Hz). Higher frequency units of measurement are primarily kHz (1000Hz) and MHz (1000kHz). For example, Wi-Fi 7 supports a maximum bandwidth of 320MHz, while Wi-Fi 6 supports a maximum bandwidth of 160MHz.

[0004] For example, the MCS (Modulation and Coding Scheme) table in the Wi-Fi 7 standard 802.11be Draft 5.0 supports 15 modulation schemes. Wi-Fi 7 is the Wi-Fi standard, specifically the 802.11BE protocol defined by the Institute of Electrical and Electronics Engineers (IEEE), also known as 802.11EHT (Extremely High Throughput). Compared to Wi-Fi 6, Wi-Fi 7 supports a higher order of Quadrature Amplitude Modulation (QAM), specifically 4096-QAM. One modulated symbol can transmit 12 binary bits. Generally, the higher the MCS index, the higher the modulation order, and the higher the number of effective bits that can be carried. A typical MCS table is defined for a single resource unit (RU). This table generally contains two parts: modulation scheme and code rate. For example, Table 1 below shows the EHT-MCS (Extremely High Throughput Modulation and Coding Scheme) table corresponding to a carrier. This table is specifically used to assign modulation and coding indexes (MSC indexes) to RUs with 106-tone (106 carriers) in Wi-Fi 7, and is a type of MSC table. Table 1: EHT-MCS table corresponding to 106 carriers, number of spatial streams (N) SS，u =1 (excerpt)

[0005] Wherein: QPSK, 16-QAM, 64-QAM, and 4096-QAM indicate that quadrature phase shift keying (QPSK) is used, in which case each modulated symbol can transmit 2 bits of binary information; 16-QAM can transmit 4 bits; 64-QAM can transmit 6 bits; and 4096-QAM can transmit 8 bits. The code rate Ru is the ratio between useful bits and total transmitted bits (useful + redundant bits), used to measure the redundancy added by the physical layer. Redundant bits are used for forward error correction (FEC). N BPSCS This represents the number of coded bits on each carrier in each spatial stream (in other words, N). BPSCSis the number of coded bits per subcarrier per spatial stream). N CBPS This represents the number of bits encoded in each Orthogonal Frequency Division Multiplexing (OFDM) symbol (in other words, N). CBPS is the number of coded bits per OFDM symbol). N DBPS This represents the number of bits contained in each OFDM symbol before encoding (in other words, N). DBPS is the number of data bits per OFDM symbol). N SS N represents the number of spatial flows (in other words, N) SS (This is the number of spatial streams). The last few columns in the table represent the corresponding data rates for different guard intervals (GI).

[0006] Wi-Fi access points need to frequently or intermittently measure the channel to obtain channel conditions (such as signal-to-noise ratio), and then determine the modulation and coding scheme index (MSC index) for the next transmitted data. Generally, the MSC index is chosen to satisfy a combination of modulation and coding schemes that meet the signal-to-noise ratio (SNR) or Eb / N0 requirements to achieve maximum spectral efficiency. For example, simulations are used to determine the bit error rate (BER) of various modulation schemes at different coding rates for different SNR values, thereby selecting appropriate modulation and coding schemes. In the context of transmitting a single RU, this means selecting a suitable MSC index from the corresponding MSC table in the standard.

[0007] Meanwhile, to solve the problem of long-distance coverage or the coverage of long-distance terminals, Wi-Fi 6 has proposed a new frame format, HE ER SU PPDU, where the abbreviations mean High Efficiency (HE), Extended Range (ER), Single User (SU), Physical Layer (PHY), and Protocol Data Unit (PPDU) in sequence. However, this new frame format can only be transmitted on a 20MHz bandwidth and limits the RUs it supports to 242-tone or 106-tone RUs. At the same time, it restricts the supported modulation and spatial streams. For a 242RU <MSC index and spatial stream>, it will be limited to <HE-MCS 0,1>, <HE-MCS 1,1>, and <HE-MCS2,1>. For a 106RU <MSC index and spatial stream>, it will be limited to <HE-MCS 0,1>, <HE-MCS1,1>, and <HE-MCS2,1>.

[0008] The inventors found that there are at least the following problems in the related technologies: The way to select the MCS index is generally based on maximizing spectral efficiency and making corresponding selections according to the minimum bit error rate (BER), or block error rate (BLER) corresponding to the MCS index. However, in some cases, it is necessary to ensure ultra-long-distance coverage of the access point (AP), or other requirements, such as increasing the reliability of Wi-Fi signals to support certain special terminals. In this case, this selection method cannot meet the requirements.

[0009] Regarding the method corresponding to the new frame format proposed by Wi-Fi 6 mentioned above, the restrictions on modulation methods, spatial streams, and RUs are relatively strict, and it is only suitable for transmitting services with relatively low data rates. With the emergence of various application scenarios, such as Virtual Reality (VR) or Extended Reality (XR), this method cannot be used when high-reliable transmission of large amounts of data is required. Summary of the Invention

[0010] The purpose of this invention is to provide a modulation and coding strategy selection method, apparatus, terminal, and storage medium that, in the case of long-distance transmission, not only can it meet the increasing data transmission demands, but it also ensures sufficient coverage while guaranteeing that the data transmission rate is not reduced due to the distance. With the same transmission power, it expands the coverage of the Wi-Fi access point, enabling normal communication for terminals located far from the access point, while also ensuring a sufficiently fast and reliable data transmission rate.

[0011] To address the aforementioned technical problems, embodiments of the present invention provide a modulation and coding strategy selection method, comprising: restricting certain features in a modulation and coding strategy table when the distance to an access point exceeds a preset distance; and, when the distance to the access point exceeds the preset distance, selecting a modulation and coding index in the modulation and coding strategy table based on the restricted features to obtain a first modulation and coding index, and then correcting the first modulation and coding index to a second modulation and coding index using a modulation and coding index margin; wherein, restricting certain features in the modulation and coding strategy table includes: restricting certain rows in the modulation and coding strategy table, wherein all parameters in the restricted rows are made unavailable; and / or, restricting the number of spatial streams in the modulation and coding strategy table, so that certain operating modes cannot be configured as enabled.

[0012] Embodiments of the present invention also provide a modulation and coding strategy selection device, comprising: a feature restriction module, configured to restrict certain features in a modulation and coding strategy table when the distance between the device and the access point exceeds a preset distance; and a margin correction module, configured to, when the distance between the device and the access point exceeds a preset distance, after selecting a modulation and coding index in the modulation and coding strategy table based on the restricted features to obtain a first modulation and coding index, correct the first modulation and coding index to a second modulation and coding index by using a modulation and coding index margin; wherein, restricting certain features in the modulation and coding strategy table includes: restricting certain rows in the modulation and coding strategy table, wherein all parameters in the restricted rows are put into an unavailable state; and / or, restricting the number of spatial streams in the modulation and coding strategy table, so that certain operating modes cannot be configured to an enabled state.

[0013] Embodiments of the present invention also provide a terminal, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the modulation and coding strategy selection method described above.

[0014] Embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-described modulation and coding strategy selection method.

[0015] In this embodiment of the invention, when the distance to the access point exceeds a preset distance, certain features in the modulation and coding strategy table are restricted; for example, certain rows in the modulation and coding strategy table are restricted, and all parameters in the restricted rows become unavailable; and / or, the number of spatial streams in the modulation and coding strategy table is restricted, so that certain operating modes cannot be configured as enabled. After selecting a modulation and coding index based on the restricted features in the modulation and coding strategy table to obtain a first modulation and coding index, the first modulation and coding index is corrected to a second modulation and coding index using the modulation and coding index margin. The advantage of this is that, under the same transmit power, it expands the coverage of the access point, enabling terminals farther from the access point to communicate normally, while also ensuring a sufficiently fast data transmission rate. This ensures that in the case of long-distance transmission, it not only meets the increasing data transmission demand but also ensures that the data transmission rate is not reduced due to the long distance while maintaining sufficient coverage. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 is a flowchart of a modulation and coding strategy selection method according to an embodiment of the present invention;

[0018] Figure 2 is a flowchart of an access point initiating modulation and coding strategy negotiation according to an embodiment of the present invention;

[0019] Figure 3 is a flowchart of a terminal-initiated modulation and coding strategy negotiation according to an embodiment of the present invention;

[0020] Figure 4 is a schematic diagram of the modulation and coding strategy selection device according to another embodiment of the present invention;

[0021] Figure 5 is a schematic diagram of the terminal structure according to another embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of the present invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0023] One embodiment of the present invention relates to a modulation and coding strategy selection method, which can be applied to any terminal device that can wirelessly connect to an access point, such as mobile phones, computers, and other terminal devices. In this embodiment, when the distance between the terminal device and the access point exceeds a preset distance, some features in the modulation and coding strategy table are restricted; for example, some rows in the modulation and coding strategy table are restricted, and all parameters in the restricted rows are made unavailable; and / or, the number of spatial streams in the modulation and coding strategy table is restricted so that some operating modes cannot be configured as enabled. After selecting a modulation and coding index based on the restricted features in the modulation and coding strategy table to obtain a first modulation and coding index, the first modulation and coding index is corrected to a second modulation and coding index by using the modulation and coding index margin. The advantage of doing so is that, under the same transmit power, it not only expands the coverage of the access point, enabling terminals farther from the access point to communicate normally, but also ensures that the data transmission rate is fast and reliable enough. This ensures that in the case of long-distance transmission, it can not only meet the increasing data transmission demand, but also ensure that the coverage is wide enough while ensuring that the data transmission rate is not reduced due to the distance. The following is a detailed description of the implementation details of the modulation and coding strategy selection method in this embodiment. The following content is only for the convenience of understanding the implementation details and is not necessary for implementing this solution.

[0024] As shown in Figure 1, in step 101, if the distance between the terminal device and the access point exceeds a preset distance, some features in the modulation and coding strategy table are restricted. The restriction on some features in the modulation and coding strategy table can be: restricting some rows in the modulation and coding strategy table, so that all parameters in the restricted rows enter an unavailable state; or it can be restricting the number of spatial streams in the modulation and coding strategy table so that some working modes cannot be configured as enabled.

[0025] The restrictions on certain parts of the table are taken into consideration in scenarios where it is necessary to ensure ultra-long-distance coverage of access points (APs) or other requirements, such as increasing the reliability of Wi-Fi signals to support certain special terminals. In these cases, it is not appropriate to simply choose the modulation and coding index (MSC index) with the sole aim of maximizing spectral efficiency or minimizing BER. When a terminal is far from the access point, it is preferable to choose a lower modulation order and a lower coding rate. This is because choosing a lower modulation order allows the terminal or access point to still demodulate correctly when receiving signals with a low signal-to-noise ratio (SNR). On the other hand, a lower coding rate also gives the terminal or access point stronger error correction capabilities. As is well known, erroneous bits are more likely to occur at low SNR. Choosing a lower coding rate can effectively address this issue. To ensure long-distance coverage of terminals by the AP or to increase the reliability of the Wi-Fi signal, this can be achieved by reserving a certain SNR margin when selecting the MCS index, or by setting certain MCS indices in the standard's MSC table to be unavailable. The combined effect of these two methods is even better. It is clear from the above that restricting certain features in the modulation and coding strategy table is quite effective.

[0026] In one example, restricting certain features in the modulation and coding strategy table could involve restricting certain rows in the MCS table of a specific resource unit (RU), rendering these restricted rows unusable. The MCS table for this RU is similar to Table 1 above. This restriction can also be applied to MCS tables for other types of resource units, which will not be listed here. In some cases, the restricted rows may share a common modulation scheme, such as 1024-QAM, or a common coding rate, such as 5 / 6. In other cases, some restricted rows may contain guard intervals (GIs), meaning that after restriction, these GIs and their corresponding transmission rates will be unavailable. It is straightforward and obvious that, in one example, after restricting certain feature parameters in the modulation and coding strategy table (e.g., Table 1 above) to an unusable state, the available modulation schemes in the modulation and coding strategy table include: BPSK with a code rate of 1 / 2 and QPSK with a code rate of 1 / 2.

[0027] In one example, restricting certain features in the modulation and coding strategy table can also render certain frame formats unavailable or disabled for terminals located far from the access point. For instance, this might include Multi-User Transmit Request (MU-RTS) trigger frames, or disabling Multi-User Multiple-Input Multiple-Output (MU-MIMO) transmission, meaning either uplink or downlink MU-MIMO transmission is not supported. This achieves better coverage. Because MU-MIMO transmission requires good spatial isolation, to avoid interference from other users in the same group, in one example, the terminal does not support MU-MIMO transmission.

[0028] In one example, restricting certain features in the modulation and coding strategy table can be achieved by limiting certain parameters, thereby restricting the operating mode of the terminal device. For instance, in some cases, the terminal may not support multiple data stream transmissions, such as not supporting more than two data streams. Similar data stream transmissions also require good spatial isolation. Because the terminal is far from the associated access point, spatial isolation cannot be ideal, so the number of supported spatial streams needs to be limited. For example, if a terminal is far from the access point (e.g., greater than 500m), certain operating modes may not be enabled, or may not be configured to be enabled; for example, limiting the number of spatial streams to no more than two. It is straightforward and obvious that, in one example, specifying parameter information to meet the corresponding preset restriction could mean limiting the number of spatial streams to one.

[0029] Limit the number of spatial streams in the modulation and coding strategy table so that some operating modes cannot be configured to be enabled. Alternatively, limit the number of transmit or receive antennas to no less than two. Since multiple antennas transmit, resulting in more signal energy, this limitation allows terminal devices to better utilize spatial diversity.

[0030] In one example, when the distance between the terminal device and the access point exceeds a preset distance, the size, type, and bandwidth occupied by resource units can be restricted. There are various ways to restrict resource units. For example: in some cases, terminals farther from the access point may be restricted from using smaller RUs (e.g., RUs with fewer than 106 carriers). In some cases, terminals farther from the access point may be restricted to using only regular RUs. In some cases, terminals farther from the access point may be restricted to using only distributed RUs. This is a newly defined RU where carrier resources are interleaved with other RUs of the same type in the OFDM symbol frequency domain. In some cases, terminals farther from the access point may not support RUs with a bandwidth greater than a certain value. For example, certain RUs or multiple resource units (MRUs) occupying bandwidths greater than 20MHz, 40MHz, or 80MHz. This RU can be a regular RU or a distributed RU. In some cases, due to factors such as terminal data volume, larger RUs may not be used to avoid consuming excessive energy for transmission. In some cases, terminals located far from the access point do not support the use of RUs with bandwidth less than a certain value. For example, when using Data Recording Units (dRUs), frequency domain diversity benefits can only be obtained if the bandwidth occupied by the dRU is large enough. This includes RUs or multiple resource units (MRUs) that occupy bandwidth greater than 20MHz, 40MHz, or 80MHz.

[0031] In one example, when the distance to the access point exceeds a preset distance, the frequency of the bandwidth used for data transmission is limited, ensuring that the frequency cannot exceed the preset frequency. For instance, in certain situations, the terminal cannot use a bandwidth exceeding a certain limit for data transmission. For example, when the terminal is far from the associated AP, greater than 200 meters, it cannot use a bandwidth exceeding 80MHz for data transmission. One possibility is that the terminal consumes more power due to the greater distance from the AP, requiring a relatively narrower bandwidth for transmission.

[0032] In one example, if the distance between the terminal device and the access point exceeds a preset distance, the size of the transmitted data packets is limited so that the size of the transmitted data packets cannot exceed the preset data packet size; for example, in some cases, terminals that are far from the access point do not support or are configured not to transmit data packets larger than a certain size.

[0033] In one example, if the distance to the access point exceeds a preset distance, the types of data packets transmitted are restricted. For instance, in some cases, terminals farther from the access point may not support, or may be configured not to transmit, certain types of data packets, such as: TB (trigger-based) PPDU, SU (Single User) PPDU, or MU-PPDU (Multi-User Physical Layer Protocol Data Unit). Alternatively, they may only be able to transmit HE / EHT / UHR ER SU PPDU. HE / EHT / UHR respectively represent high efficiency (HE), extremely high efficiency (EHT), and ultra high reliability (EHT), which are the core features of Wi-Fi 6, Wi-Fi 7, and Wi-Fi 8.

[0034] The above restrictions are not mutually exclusive and can be freely chosen according to actual needs. In one example, the above methods are limited to applying to at least one field, at least one section, or the frame body or frame header in a frame format. Specifically: In some cases, the above restrictions, as well as the margin adjustment mentioned below, all apply to at least one field in a frame format, that is, they only work on at least one field in a frame format, or at least one section in a frame format, or the frame body or the frame header in a frame format. For example, a HE / EHT / UHR SU PPDU contains L-STF (Legacy Short Training Field), L-LTF (Legacy Long Training Field), L-SIG (Legacy Signal Field), RL-SIG (Repeated Legacy Signal Field), HE-SIG-A (High-Efficiency Signal Field), HE-STF (High-Efficiency Short Training Field), HE-LTF (High-Efficiency Long Training Field), data (Data Field), and PE (Header Field). The aforementioned constraints and margin adjustments only apply to at least one of these fields, such as data. Similarly, in a HE / EHT / UHR MU PPDU, or a HE / EHT / UHR TB PPDU, or a HE / EHT / UHR ER SU PPDU, the aforementioned constraints can be applied to at least one field in the corresponding frame.

[0035] In some cases, restricted features, such as certain rows in the MCS table or parameters in the operating mode, such as spatial flow, are included in a newly defined frame or a trigger frame. The access point transmits this information to the terminal via the trigger frame. In some cases, a newly defined frame or trigger frame contains margins, the type of the restricted frame, or the type of frames allowed to be transmitted. Alternatively, it may contain the aforementioned restrictions or margins, the type of the frame in effect, or the type of the frame in effect, and the fields that operate within the type frame.

[0036] In one example, under certain circumstances, something like this can be used.<HE-MCS 0,1> The restrictions apply to resource units. For example...<EHT-MCS a,b> Where a and b are positive integers, a > 2 and a < 5, b > 1 and b < 4. For example<UHR-MCS c,d> Let c be a variable, b be a variable, c be a variable, and d be a variable, where c > 2 and c < 5, and d > 1 and d < 4. The variables a, b, c, and d are each restricted to different ranges. These specific ranges are merely illustrative examples and are not absolute rules.

[0037] In one example, under certain circumstances, devices may need to use beamforming for transmission. For instance, if the terminal device is far from the access point (AP), beamforming is required for downlink transmission. Uplink transmission currently lacks a beamforming method; however, considering the AP's strong ability to detect uplink signals, this is not a limitation here.

[0038] In one example, parameter limitations occur related to the distance between the terminal device and the access point (AP). For instance, if the terminal is close to the AP, its transmission of smaller data packets can be limited to avoid frequent channel preemption by other terminals, or a more moderate Enhanced Distributed Channel Access (EDCA) parameter can be used. Conversely, if the terminal is far from the AP, a more aggressive EDCA parameter preemption method can be employed. In some cases, the distinction between near and far from the AP is based on one or more thresholds. For example, less than 50 meters might be considered close to the AP, while more than 100 meters might be considered far. In other cases, the type of EDCA is restricted, such as using a smaller contention window or a longer Transmission Opportunity (TXOP) duration for more distant terminals.

[0039] In step 102, if the distance between the terminal device and the access point exceeds a preset distance, the modulation and coding index is selected from the modulation and coding strategy table based on the restricted partial features to obtain the first modulation and coding index. Then, the first modulation and coding index is corrected to the second modulation and coding index by using the modulation and coding index margin.

[0040] The modulation and coding index margin here can also be called the MCS index offset, MCS index offset amount, or MCS index difference. Regardless of the name, it represents the difference between the MCS index used in actual application and the MCS index obtained through channel measurement. Table 1 is used as an example here. Other MCS tables are similar and have their corresponding MCS index offsets, which will not be elaborated further.

[0041] To facilitate understanding, an example is provided here. In one example, for a given terminal, the selected modulation coding index (MCS index) has an offset (also called the modulation coding index margin), as shown in Table 1. Some large MCS indices will be unusable. The MCS index selected using the general method is the first modulation coding index, which needs to be increased by an offset (i.e., subtracting the modulation coding index margin) to obtain the actual MCS value (the second modulation coding index). For example, in some cases, the modulation coding index margin ΔX = 2. Meanwhile, the MCS index obtained by measuring the channel is the modulation coding index value in Table 1, which is the first modulation coding index (also referred to as the EHT-MCS index to avoid confusion). Then, the first modulation coding index is corrected to the second modulation coding index, i.e., the EHT-MCS index is rolled back to EHT-MCS index - ΔX. EHT-MCS index - ΔX is then used to apply the modulation coding index value in Table 1 for modulation coding transmission information. For example, a 10% BLER calculated through channel measurement SNR, or maximizing spectral efficiency, corresponds to a modulation coding index of 10 in Table 1. Subsequently, by using a modulation coding index margin ΔX = 2, the modulation coding index applied during data transmission is 8.

[0042] By designing a margin, when transmitting to terminals located far from the access point, for example, simulations determine that the MCS index threshold is not the traditional 10% BER or BLER threshold, but rather a 5% BER or BLER threshold. In this case, the access point must choose a lower modulation order or a lower coding rate for the remote terminal. From another perspective, when selecting the MCS index, this SNR margin allows the BLER and BER of the original 10% MCS index (without margin) to reach 5% at this point. In some cases, this margin may not accurately reduce the BLER or BER to 5%, but could be other values, such as 8%, 7%, or 4%.

[0043] In one example, the modulation coding index margin is a preset value, and each modulation coding index corresponding to a resource unit has at least one modulation coding index margin. By using the modulation coding index margin, the first modulation coding index can be corrected to the second modulation coding index. This can be achieved by selecting the modulation coding index margin based on the service type of the resource unit corresponding to the first modulation coding when multiple modulation coding index margins exist, thus correcting the first modulation coding index to the second. The correspondence and settings of the margins vary, and examples will be provided below for discussion.

[0044] In some cases, the MCS indexes corresponding to each RU share only one common margin ΔX. For example, in the case mentioned above, it is 2. This margin can be any other positive integer value. The margin ΔX of the MCS index for each RU is different from the margin ΔX of the MCS index for another RU.

[0045] In some cases, each RU's MCS index has multiple margins ΔX, which are related to the RU's MCS index. For example, ΔX = (the units digit of the MCS index / 2), where the units digit of the MCS index is divided by 2 and then rounded down. In some cases, this rounding may be either up or down.

[0046] In some cases, each RU's MCS index has multiple margins ΔX, or at least one margin. This margin is obtained through simulation or is configurable. In this case, the margin exists as a vector or an array.

[0047] In some cases, each RU's MCS index has a margin ΔX of at least one (which can be a group). This margin value is tied to the service type. For example, at least ΔX for video services, at least ΔX for voice services, at least ΔX for low-latency services, and at least ΔX for other services.

[0048] In some cases, all MCS indices of the same RU share a common margin ΔX. For example, in the case mentioned above, it is 2. This margin can be any other positive integer value.

[0049] In some cases, all RUs have a common MCS index with a margin ΔX. For example, in the case mentioned above, it is 2. This margin can be any other positive integer value.

[0050] In one example, using margin to correct the modulation and coding index is a mode enabled under certain conditions. Margin mode can be activated for adjustment as long as the triggering conditions are met. By using the modulation and coding index margin, the first modulation and coding index is corrected to the second modulation and coding index. This can be achieved by: enabling margin mode when specified parameter information meets corresponding preset constraints, so that the first modulation and coding index is corrected to the second modulation and coding index using the margin in margin mode; wherein the specified parameter information includes one or any combination of the following: the bandwidth type corresponding to the terminal, the service type processed by the terminal, the channel frequency corresponding to the terminal, and the connection type corresponding to the terminal. The possibilities for triggering the margin mode are far more numerous than these. Examples of some possible situations will be given below:

[0051] In some cases, when a terminal is within a certain distance of its associated access point, the MCS index offset mode is automatically activated. In some cases, this distance is a configurable threshold, or it may be factory-determined. In others, the threshold is related to the channel's carrier frequency; for example, the higher the frequency, the smaller the threshold. In still others, the activation of the MCS index offset mode is transparent to the terminal, and all MCS calculations and selections occur at the access point.

[0052] In some cases, this margin mode only works for narrowband terminals, such as certain terminals with a bandwidth of 20MHz, or certain terminal devices with a bandwidth of 40MHz. It has no effect on terminals with operating bandwidths greater than this. It is straightforward and obvious that, in one example, specifying parameter information to meet the corresponding preset constraint could mean that the bandwidth type of the terminal is limited to 20MHz.

[0053] In some cases, this margin mode only applies to certain services, such as video or voice services. In other cases, the current terminal's MCS index margin mode is tied to a specific service. When the terminal transmits certain service modes,

[0054] In some cases, this margin mode only works in certain frequency bands or frequency zones, such as 2.4 GHz.

[0055] In some cases, this margin mode only works for certain connections, such as when the terminal is a multi-connection device.

[0056] In certain situations, this margin mode operates on the following channel frequencies (2.4GHz, 5GHz, or 6GHz), bandwidth, or the service it applies to, or the terminal type (Wi-Fi 7, Wi-Fi 6, Wi-Fi 8, or other terminals), or the connection it applies to; at least one of these can be configured. Specific configuration signaling is contained in a control frame or trigger frame. In some cases, the service it applies to is a low-latency service.

[0057] In certain situations, this margin mode is automatically activated. It is activated automatically when the terminal's MAC address falls within a certain range or contains a specific field, such as a MAC address identifier belonging to a particular manufacturer.

[0058] In certain situations, this margin mode is automatically activated. By identifying the terminal's MAC address, if it falls within a certain range or contains a certain field, such as a MAC address identifier belonging to a specific vendor, and the terminal's distance from the associated access point exceeds a certain threshold, margin mode is automatically activated.

[0059] In certain situations, this margin mode is automatically activated. By identifying the terminal's MAC address, and when the terminal is more than a certain threshold away from the associated access point, the margin mode is activated via a control frame or a trigger frame.

[0060] The configuration of margin mode does not conflict with the aforementioned methods of restricting features; this configuration can be executed independently or both can coexist. For example, margin mode can be enabled when the aforementioned feature restrictions only apply to certain connections.

[0061] In one example, the reserve mode can exit automatically: it exits when the connection to the access point is lost; it exits reserve mode upon receiving a frame from the access point carrying reserve mode cancellation information. There are various ways to end reserve mode; some possible scenarios are illustrated below:

[0062] In some cases, if the current terminal is operating in MCS index margin mode, the MCS margin mode will automatically end when the terminal leaves the current access point.

[0063] In certain situations, if the terminal is currently operating in MCS index reserve mode, due to service changes, the arrival of new services such as VR / XR services, or low-latency services, it may switch to the current reserve mode. The MCS index will be selected based on maximum throughput or highest spectral efficiency to schedule the current service.

[0064] In some cases, the access point transmits reserve mode termination information via control frames, negotiation frames, broadcast frames, or notification frames. In some cases, the termination of reserve mode is one-to-one, such as the access point transmitting the information to a specific terminal. In other cases, the termination of reserve mode is multicast or broadcast, with the access point notifying at least one terminal of the termination of reserve mode by transmitting the aforementioned frames.

[0065] In one example, a terminal supporting spare mode joins a group. Members of this group join the group through negotiation with the access point. Within the group, control frames, negotiation frames, broadcast frames, or notification frames are used to notify other terminals in the group to enable or disable spare mode. These control frames, negotiation frames, broadcast frames, or notification frames contain a group ID, group identifier, or group number. This is used to identify which specific group the terminal belongs to. In other words, the spare mode deactivation information contains the group identifier of the spare mode group. A spare mode group is formed by multiple terminals connected to the same access point and supporting spare mode, through negotiation with the access point.

[0066] In one example, an RU determines the margin or limitation of the MCS index as a pattern or set of data indicating the various limitations. This margin or limitation corresponds to a Wi-Fi 6, Wi-Fi 7, or Wi-Fi 8 terminal. This pattern or set of data is stored at the factory (or during manufacturing) on ​​the access point or terminal and is numbered. The access point transmits this number through certain frames to complete the terminal configuration. The advantage of this method is that it avoids transmitting specific data, saving air interface data transmission. This frame can be a configuration reserved in certain frames, or bits indicating the MCS index margin or certain limitations.

[0067] In one example, a segment of data is repeatedly transmitted, and then the received device combines the repeated transmissions to increase the signal-to-noise ratio and achieve coverage enhancement. That is, when sending data, the data is repeatedly transmitted; when receiving the repeated data, it is combined. For example, certain Presentation Protocol Data Units (PPDUs) are repeatedly transmitted.

[0068] In some cases, certain PPDUs, or portions of certain PPDUs, such as the data field, may be repeatedly transmitted in the frequency domain, time domain, or spatial domain (on a spatial stream). For example, certain types of PPDUs may be repeatedly transmitted, or portions of certain types of PPDUs (such as the data field) may be repeatedly transmitted. For instance, within a PPDU, a portion of data may be repeatedly transmitted in the data field. Both the original data and the repeatedly transmitted data are contained within this data field.

[0069] In some cases, data is repeatedly transmitted on RUs (Resource Units). For example, the same content may be repeatedly transmitted on the same RU or on different RUs. The retransmission methods mentioned above can be used. Transmitting the same content on different RUs includes MRU (Multiple RU) scheduling, such as simultaneously scheduling two RUs of the same size. The content transmitted on RU1 is the same as the content transmitted on RU2. This includes cases of repeated transmission within a single RU, repeated transmission within multiple RUs, and cases involving both regular RUs and distributed RUs. In multi-RU transmission, the two RUs used for repeated transmission are either regular RUs, both are distributed RUs, or one RU is a regular RU and the other is a distributed RU.

[0070] Repeated transmission can occur within a single RU or across multiple RUs. Time-domain retransmission can be used, meaning data is transmitted repeatedly over a long period. For example, at time t1, data may be transmitted on a portion of the carriers within an RU, or on all the carriers of an RU; at time t2, the retransmitted data may be transmitted on another portion of the carriers within the same RU, or on another RU involved in multi-RU transmission. Frequency-domain retransmission refers to the simultaneous transmission of the original data and the retransmitted data on different carriers within an RU, or, in multi-RU scheduling, on different RUs.

[0071] The following discussion focuses on the indication methods for repeated transmission. In some cases, a frame transmitted by the access point indicates or informs the terminal of the specific method for repeated transmission. This frame can be an initial control frame, a trigger frame, a negotiation frame, or a newly defined negotiation frame for repeated transmission. This frame contains a specific indication of the repeated transmission method, such as the repeated transmission method mentioned above, which involves repeated transmission within a RU. For example, it might indicate the repeated transmission of a portion of a data frame of a certain type. In some cases, this frame includes a field indicating whether to repeat the entire frame or a portion of the frame (the data field).

[0072] In one example, when the modulation and coding strategy selection is initiated by the access point, the data interaction is shown in Figure 2. The access point determines the terminal's parameter range, component mode, or repetitive transmission mode based on its assessment of the terminal. If the access point's notification is not broadcast, the terminal sends an acknowledgment character (ACK) upon receiving the notification; otherwise, it does not send anything. When the modulation and coding strategy selection is initiated by the access point, the data interaction is shown in Figure 3. The terminal reports its status (location) or request information. The access point determines the terminal's parameter range, component mode, or repetitive transmission mode based on the reported status (location) or request information. If the access point's notification is not broadcast, the terminal sends an ACK upon receiving the notification; otherwise, it does not send anything. In some cases, the notification is included in a trigger frame. Upon receiving the trigger frame, the terminal receives data frames according to the trigger frame's instructions and then sends an ACK or a batch ACK. In other cases, upon receiving the trigger frame, the terminal sends uplink data according to the trigger frame's instructions.

[0073] In some cases, the notification frame can be an initial control frame, a trigger frame, a negotiation frame, or a newly defined frame used to configure the terminal parameter range or operating mode. In other cases, upon receiving the notification frame, the terminal may not execute the parameter limitations, margins, or retransmission methods specified in the notification frame; the notification frame is merely a suggestion. The terminal provides feedback on its execution in the ACK frame, for example, by only executing the parameter retransmission method.

[0074] In some cases, upon receiving a notification frame, the terminal needs to execute the parameters specified in the frame, or the remaining parameters, or the repeated transmission method. The signaling in the notification frame is a requirement for execution. The terminal provides feedback on its execution status in the ACK frame. Alternatively, if the terminal is required to execute the signaling or command content of the notification frame by default, it does not need to be confirmed again in the ACK. The purpose of the ACK is simply to acknowledge receipt of the notification frame.

[0075] In some cases, a notification frame is accompanied by uplink or downlink data transmission that conforms to the requirements of the notification frame. Afterwards, if the receiver correctly receives the data, it sends an ACK to the data sender. Otherwise, the receiver does not transmit an ACK.

[0076] In some cases, there is no need for the access point and terminal to negotiate data transmission as shown in Figures 2 and 3. The aforementioned limiting, margin mode, or repeated transmission mode can be directly activated. For example, the signal-to-noise ratio obtained by measuring the channel may meet the requirements of a high modulation scheme, but a lower signal-to-noise ratio may be intentionally indicated and used to ensure transmission robustness. Alternatively, as shown above, when the distance between the terminal and the access point exceeds a certain threshold, limiting, margin mode, or repeated transmission mode can be automatically activated.

[0077] In some cases, a negotiation method similar to Figure 3 will be used. The AP sends an MRQ (MRQ stands for MFB requester, and MFB stands for MCS feedback) to the terminal, and the terminal transmits the MFB back to the AP. The AP then decides on the parameters and format of the subsequent downlink data frames based on its own circumstances. In some cases, the AP and the base station reuse the MCS feedback mechanism, determining the MSC index or other parameter constraints listed above based on the terminal's suggestions.

[0078] In some cases, the methods described above for limiting certain characteristics of data transmission steps, or for MCS index margins, or for repeated transmissions, apply to multicast frames other than beacon frames.

[0079] In some cases, the aforementioned limitations, such as bandwidth, spatial stream, and PPDU type, are contained in the transmit vector (TxVector) or receive vector (RxVector) and transmitted to the terminal or access point via control frames, MFQs, or MFBs. Alternatively, they may be contained in the UHR capability element (UHR stands for Ultra High Reliable) or the PHY capability element (PHY stands for Physical Layer).

[0080] In this embodiment, when the distance between the terminal device and the access point exceeds a preset distance, certain features in the modulation and coding strategy table are restricted. For example, certain rows in the modulation and coding strategy table are restricted, and all parameters in the restricted rows become unavailable. And / or, the number of spatial streams in the modulation and coding strategy table is restricted so that certain operating modes cannot be configured as enabled. After selecting a modulation and coding index from the modulation and coding strategy table based on the restricted features to obtain a first modulation and coding index, the first modulation and coding index is corrected to a second modulation and coding index using the modulation and coding index margin. The advantage of this is that, under the same transmit power, it expands the coverage of the access point, enabling terminals farther from the access point to communicate normally, while also ensuring a sufficiently fast data transmission rate. This ensures that in long-distance transmission, it not only meets the increasing data transmission demands but also guarantees sufficient coverage while ensuring that the data transmission rate is not reduced due to the greater distance.

[0081] The steps described above are for clarity only. In practice, they can be combined into one step or some steps can be split into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this application. Adding insignificant modifications or introducing insignificant designs to the algorithm or process, but without changing the core design of the algorithm and process, are also within the scope of protection of this application.

[0082] Another embodiment of the present invention relates to a modulation and coding strategy selection method, comprising: when the distance between the device and the access point exceeds a preset distance, restricting some feature parameters in the modulation and coding strategy table to their respective preset feature intervals, and / or restricting some feature parameters in the modulation and coding strategy table to an unavailable state; wherein, some feature parameters in the modulation and coding strategy table include the number of spatial streams, and restricting some feature parameters in the modulation and coding strategy table to their respective preset feature intervals includes: restricting the number of spatial streams to a preset feature interval corresponding to the number of spatial streams; wherein, restricting some feature parameters in the modulation and coding strategy table to an unavailable state includes: restricting all feature parameters in some rows of the modulation and coding strategy table to an unavailable state; wherein, the specified parameter information includes one or any combination of the following: the bandwidth type corresponding to the terminal, the service type processed by the terminal, the channel frequency corresponding to the terminal, and the connection type corresponding to the terminal.

[0083] The above embodiments explicitly state that "to ensure long-distance coverage of the AP terminal or increase the reliability of the Wi-Fi signal, this can be achieved by reserving a portion of the SNR margin when selecting the MCS index, or by setting certain MCS indices in the MSC table of the standard to be unavailable." It is easy to see that this embodiment refers to the part mentioned in the above method embodiments where "this can also be achieved by setting certain MCS indices in the MSC table of the standard to be unavailable." The part where "this can be achieved by reserving a portion of the SNR margin when selecting the MCS index" includes related embodiments such as "after selecting the modulation and coding index in the modulation and coding strategy table based on the restricted partial characteristic parameters to obtain the first modulation and coding index, the first modulation and coding index is corrected to the second modulation and coding index by using the modulation and coding index margin," which are not required in this embodiment. The relevant technical details mentioned in the above method embodiments are still valid in this embodiment. For example, this embodiment also includes: when transmitting data as the transmitting side, repeatedly transmitting data within multiple ordinary RUs or multiple distributed RUs in the frequency domain; and some characteristic parameters in the modulation and coding strategy table also include: the type of transmitted data packets, etc. To reduce repetition, the embodiments mentioned in the above method embodiments will not be elaborated further here.

[0084] Another embodiment of the present invention relates to a modulation and coding strategy selection device, as shown in FIG4, comprising: a feature restriction module 401, used to restrict some features in the modulation and coding strategy table when the distance between the device and the access point exceeds a preset distance; and a margin correction module 402, used to, when the distance between the device and the access point exceeds the preset distance, select a modulation and coding index in the modulation and coding strategy table based on the restricted features to obtain a first modulation and coding index, and then correct the first modulation and coding index to a second modulation and coding index by using the modulation and coding index margin; wherein, restricting some features in the modulation and coding strategy table includes: restricting some rows in the modulation and coding strategy table, wherein all parameters in the restricted rows are put into an unavailable state; and / or, restricting the number of spatial streams in the modulation and coding strategy table so that some operating modes cannot be configured to an enabled state.

[0085] In one example, the device further includes: a resource limiting module, used to limit the size, type, and bandwidth occupied of resource units when the distance to the access point exceeds a preset distance; and / or, when the distance to the access point exceeds a preset distance, to limit the frequency of the bandwidth used when transmitting data, so that the frequency of the bandwidth used when transmitting data cannot exceed a preset frequency; and / or, when the distance to the access point exceeds a preset distance, to limit the size of the transmitted data packets, so that the size of the transmitted data packets cannot exceed a preset data packet size; and / or, when the distance to the access point exceeds a preset distance, to limit the type of transmitted data packets.

[0086] In one example, the functions performed by the various modules of the device are limited to being effective in at least one field, or at least one frame body, or at least one frame header in a frame format.

[0087] In one example, the modulation coding index margin is a preset value, and each modulation coding index corresponding to a resource unit has at least one modulation coding index margin; by using the modulation coding index margin, the first modulation coding index is corrected to the second modulation coding index, including: when the first modulation coding has multiple modulation coding index margins, the modulation coding index margin is selected according to the service type of the resource unit corresponding to the first modulation coding to correct the first modulation coding index to the second modulation coding index.

[0088] In one example, modifying the first modulation and coding index to the second modulation and coding index by using modulation and coding index margin includes: when the specified parameter information meets the corresponding preset constraint conditions, enabling the margin mode, so as to modify the first modulation and coding index to the second modulation and coding index by using the modulation and coding index margin in the margin mode; wherein, the specified parameter information includes one of the following or any combination thereof: the bandwidth type corresponding to the terminal, the service type processed by the terminal, the channel frequency corresponding to the terminal, and the connection type corresponding to the terminal.

[0089] In one example, the device further includes: a reserve mode switching module, used to automatically exit reserve mode when disconnected from the access point; and to exit reserve mode after receiving a frame carrying reserve mode cancellation information sent by the access point; wherein the reserve mode cancellation information contains a group identifier of the reserve mode group, and the reserve mode group is formed by multiple terminals connected to the same access point and supporting the enabling of reserve mode through negotiation with the access point.

[0090] In one example, the apparatus further includes: a retransmission module for retransmitting data when transmitting data as a sending side; and merging the retransmitted data after receiving it as a receiving side.

[0091] In this embodiment, when the distance between the terminal device and the access point exceeds a preset distance, certain features in the modulation and coding strategy table are restricted. For example, certain rows in the modulation and coding strategy table are restricted, and all parameters in the restricted rows become unavailable. And / or, the number of spatial streams in the modulation and coding strategy table is restricted so that certain operating modes cannot be configured as enabled. After selecting a modulation and coding index from the modulation and coding strategy table based on the restricted features to obtain a first modulation and coding index, the first modulation and coding index is corrected to a second modulation and coding index using the modulation and coding index margin. The advantage of this is that, under the same transmit power, it expands the coverage of the access point, enabling terminals farther from the access point to communicate normally, while also ensuring a sufficiently fast data transmission rate. This ensures that in long-distance transmission, it not only meets the increasing data transmission demands but also guarantees sufficient coverage while ensuring that the data transmission rate is not reduced due to the greater distance.

[0092] It is not difficult to see that this embodiment is a device embodiment corresponding to the above method embodiments, and this embodiment can be implemented in conjunction with the above method embodiments. The relevant technical details mentioned in the above method embodiments are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the above method embodiments.

[0093] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent from this embodiment.

[0094] Another embodiment of the present invention relates to a terminal, as shown in FIG5, including at least one processor 501; and a memory 502 communicatively connected to the at least one processor; wherein the memory 502 stores instructions executable by the at least one processor 501, the instructions being executed by the at least one processor 501 to enable the at least one processor 501 to perform the modulation and coding strategy selection method as described above.

[0095] The memory 502 and processor 501 are connected via a bus, which can include any number of interconnecting buses and bridges. The bus connects various circuits of one or more processors 501 and memory 502 together. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. A bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by processor 501 is transmitted over a wireless medium via an antenna, which further receives data and transmits it to processor 501.

[0096] Processor 501 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory 502 can be used to store data used by processor 501 during operation.

[0097] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the method embodiments described above.

[0098] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0099] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A modulation and coding strategy selection method, comprising: If the distance between the access point and the access point exceeds a preset distance, some feature parameters in the modulation and coding strategy table will be restricted to their respective preset feature ranges, and / or some feature parameters in the modulation and coding strategy table will be restricted to an unavailable state. If the distance between the access point and the access point exceeds a preset distance, after selecting the modulation and coding index in the modulation and coding strategy table based on the restricted partial feature parameters to obtain the first modulation and coding index, the first modulation and coding index is corrected to the second modulation and coding index by using the modulation and coding index margin. The modulation and coding strategy table includes the number of spatial streams as some of its feature parameters. The step of restricting some feature parameters in the modulation and coding strategy table to their respective preset feature intervals includes: restricting the number of spatial streams to the preset feature intervals corresponding to the number of spatial streams, so that some operating modes cannot be configured as enabled. Specifically, restricting some feature parameters in the modulation and coding strategy table to be unavailable includes: restricting all feature parameters in some rows of the modulation and coding strategy table to an unavailable state; The step of correcting the first modulation and coding index to the second modulation and coding index by using modulation and coding index margin includes: when the specified parameter information meets the corresponding preset constraint conditions, opening the margin mode, so as to correct the first modulation and coding index to the second modulation and coding index by using the modulation and coding index margin in the margin mode. The specified parameter information includes one or any combination of the following: The bandwidth type of the terminal, the service type processed by the terminal, the channel frequency of the terminal, and the connection type of the terminal.

2. The modulation and coding strategy selection method according to claim 1, wherein, The method further includes: If the distance between the access point and the access point exceeds a preset distance, restrictions will be placed on the size, type, and bandwidth occupied by resource units; and / or, If the distance to the access point exceeds a preset distance, the frequency of the bandwidth used for data transmission is limited so that the frequency of the bandwidth used for data transmission cannot exceed a preset frequency; and / or, If the distance to the access point exceeds a preset distance, the size of the transmitted data packets is limited to ensure that the size of the transmitted data packets does not exceed a preset data packet size; and / or, If the distance between the data packet and the access point exceeds a preset distance, the type of data packet transmitted will be restricted.

3. The modulation and coding strategy selection method according to claim 1 or 2, wherein, The method is limited to being effective on at least one field, or at least one section, or at least the frame body, or the frame header in a frame format.

4. The modulation and coding strategy selection method according to claim 1, wherein, The modulation and coding index margin is a preset value, and each modulation and coding index corresponding to a resource unit has at least one modulation and coding index margin. The step of correcting the first modulation and coding index to the second modulation and coding index by using modulation and coding index margin includes: When the first modulation code has multiple modulation code index reserves, the modulation code index reserves are selected according to the service type of the resource unit corresponding to the first modulation code, so as to correct the first modulation code index to the second modulation code index.

5. The modulation and coding strategy selection method according to claim 1, wherein, The method further includes: When disconnected from the access point, the system automatically exits the margin mode. Upon receiving a frame from the access point carrying the information to cancel the reserve mode, the system exits the reserve mode. The margin mode cancellation information includes a group identifier for the margin mode group, which is formed by multiple terminals connected to the same access point and supporting the enabling of the margin mode through negotiation with the access point.

6. The modulation and coding strategy selection method according to claim 1, wherein, The method further includes: When transmitting data as the transmitting side, the data is repeatedly transmitted within multiple ordinary RUs or multiple distributed RUs in the frequency domain. After receiving duplicate data as the receiving side, the duplicate data is merged.

7. The modulation and coding strategy selection method according to claim 1, wherein, The method further includes: After restricting some feature parameters in the modulation and coding strategy table to an unavailable state, the modulation schemes in the modulation and coding strategy table that are available include: BPSK with a code rate of 1 / 2 and QPSK with a code rate of 1 / 2.

8. The modulation and coding strategy selection method according to claim 1, wherein, The modulation and coding strategy table also includes some characteristic parameters such as the frequency of the bandwidth used when transmitting data and the type of data packets transmitted. The step of restricting some feature parameters in the modulation and coding strategy table to their respective preset feature ranges also includes: limiting the number of spatial streams to 1 and limiting the frequency of the bandwidth used when transmitting data to 20MHz.

9. A modulation and coding strategy selection device, comprising: The feature restriction module is used to restrict some feature parameters in the modulation and coding strategy table to their respective preset feature ranges when the distance between the module and the access point exceeds a preset distance, and / or to restrict some feature parameters in the modulation and coding strategy table to an unavailable state. The margin correction module is used to correct the first modulation and coding index to a second modulation and coding index when the distance between the access point and the access point exceeds a preset distance, after selecting the modulation and coding index in the modulation and coding strategy table based on the restricted partial characteristics to obtain the first modulation and coding index. The modulation and coding strategy table includes the number of spatial streams as some of its feature parameters. The step of restricting some feature parameters in the modulation and coding strategy table to their respective preset feature intervals includes: restricting the number of spatial streams to the preset feature intervals corresponding to the number of spatial streams, so that some operating modes cannot be configured as enabled. Specifically, restricting some feature parameters in the modulation and coding strategy table to be unavailable includes: restricting all feature parameters in some rows of the modulation and coding strategy table to an unavailable state; The step of correcting the first modulation and coding index to the second modulation and coding index by using modulation and coding index margin includes: when the specified parameter information meets the corresponding preset constraint conditions, opening the margin mode, so as to correct the first modulation and coding index to the second modulation and coding index by using the modulation and coding index margin in the margin mode. The specified parameter information includes one or any combination of the following: The bandwidth type of the terminal, the service type processed by the terminal, the channel frequency of the terminal, and the connection type of the terminal.

10. A terminal, comprising: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the modulation and coding strategy selection method as described in any one of claims 1 to 8.

11. A modulation and coding strategy selection method, comprising: If the distance between the access point and the access point exceeds a preset distance, some feature parameters in the modulation and coding strategy table will be restricted to their respective preset feature ranges, and / or some feature parameters in the modulation and coding strategy table will be restricted to an unavailable state. The modulation and coding strategy table includes the number of spatial streams as some of its feature parameters. The step of limiting some feature parameters in the modulation and coding strategy table to their respective preset feature intervals includes limiting the number of spatial streams to the preset feature intervals corresponding to the number of spatial streams. Specifically, restricting some feature parameters in the modulation and coding strategy table to be unavailable includes: restricting all feature parameters in some rows of the modulation and coding strategy table to an unavailable state; The specified parameter information includes one or any combination of the following: The bandwidth type corresponding to the terminal, the service type processed by the terminal, the channel frequency corresponding to the terminal, and the connection type corresponding to the terminal; The method further includes: when transmitting data as a transmitting side, repeatedly transmitting the data within multiple ordinary RUs or multiple distributed RUs in the frequency domain.

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