CN118784147A - Modulation and coding strategy selection method, device, terminal and storage medium - Google Patents

Abstract

The embodiments of the present invention relate to the field of wireless communication technology, and disclose a modulation and coding strategy selection method, device, terminal and storage medium. In the present invention, when the distance to the access point exceeds the 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/or the number of spatial streams is restricted. After selecting the modulation and coding index in the modulation and coding strategy table based on the restricted partial features 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; so that in the case of long-distance transmission, it can not only meet the gradually increasing data transmission requirements, but also ensure that the coverage is wide enough while also ensuring that the data transmission rate is not reduced due to the influence of the long distance.

Description

Modulation and coding strategy selection method, device, terminal and storage medium

Technical Field

The embodiments of the present invention relate to the field of wireless communication technology, and in particular to a modulation and coding strategy selection method, device, terminal and storage medium.

Background Art

In order to meet various application scenarios and support various services and application scenarios, Wi-Fi technology continues to evolve. In order to improve throughput, Wi-Fi supports multiple modulation and coding methods, and the spatial stream, number of antennas, bandwidth, etc. are also gradually enhanced. For example, the maximum bandwidth supported by Wi-Fi 7 is 320MHz, while the maximum bandwidth supported by Wi-Fi 6 is 160MHz.

For example, the MCS (Modulation and Coding Scheme) table of Wi-Fi 7 standard 802.11be Draft 5.0 supports 15 modulation methods. Among them, Wi-Fi 7 is the Wi-Fi standard, namely 802.11BE formulated by the IEEE protocol, also known as 802.11EHT (Extremely High Throughput). Compared with Wi-Fi 6, Wi-Fi 7 supports a higher-order modulation method 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. Generally, an MCS table is defined for a resource unit (RU). The table generally contains two parts: modulation scheme (Modulation) and code rate (Code Rate). Taking the following Table 1 as an example, the EHT-MCS (Extremely High Throughput - Modulation and Coding Strategy) table corresponding to the carrier is specifically used to allocate the modulation and coding index (MSC index) for the 106-tone (106 carriers) RU in Wi-Fi 7, which is a type of MSC table.

Where: QPSK, 16-QAM, 64QAM and 4096QAM mean that when using QPSK, each modulated symbol can transmit 2 bits of binary information, when using 16QAM, 4 bits can be transmitted, when using 64QAM, 6 bits can be transmitted, and when using 256QAM, 8 bits can be transmitted. Code rate _Ru : It is the ratio between useful bits and total transmitted bits (useful + redundant bits), which is used to measure the redundancy added by the physical layer. Redundant bits are used for forward error correction (FEC). N _BPSCS represents the number of coded bits per carrier per spatial stream (in other words, N _BPSCS is the number of coded bits per subcarrier per spatial stream). N _CBPS represents the number of coded bits per Orthogonal Frequency Division Multiplex (OFDM) symbol (in other words, N _CBPS is the number of coded bits per OFDM symbol). N _DBPS represents the number of bits contained in each OFDM symbol before coding (in other words, N DBPS is the number of data bits per OFDM symbol). N _SS represents the number of spatial streams (in other words, N _SS is the number of spatial streams). The following columns in the table represent the corresponding data rates for different guard intervals (GI).

Wi-Fi access points need to measure channels frequently or intermittently to obtain channel conditions (such as signal-to-noise ratio), and then determine the modulation and coding index (MSC index) for the next data transmission. Generally, the MSC index selects a combination of modulation and coding methods that satisfies the signal-to-noise ratio (SNR) or Eb/N0 to achieve maximum spectral efficiency. For example, the bit error rate (BER) of each modulation method at different coding rates under various signal-to-noise ratio values is determined through simulation, so as to select the appropriate modulation and coding method. When transmitting an RU, it is to select a suitable modulation and coding index (MCS index) in the corresponding MSC table in the standard.

At the same time, in order to solve the problem of long-distance coverage or the coverage problem of long-distance terminals, Wi-Fi 6 proposes a new frame format HE ER SU PPDU, where the abbreviations are high efficiency (HE), extended range (ER), single user (SU), physical layer (PHY), and protocol data unit (PPDU). However, this new frame format can only be transmitted on a bandwidth of 20MHz, and the RUs it supports transmission are limited to 242-tone or 106-tone RUs. At the same time, the supported modulation and spatial streams are limited. 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>.

The inventors have found that there are at least the following problems in the related art: the method of selecting the MCS index is generally based on maximizing the spectrum efficiency, and the corresponding selection is made according to the minimized bit error rate (BER) or block error rate (BLER) corresponding to the MCS index. However, in some cases, it is necessary to ensure the coverage of the AP over a long distance, or other requirements, such as increasing the reliability of the Wi-Fi signal, so as to support certain special terminals. In this case, this selection method cannot meet the requirements.

For the Wi-Fi 6 mentioned above, a new frame format method is proposed, which has strict restrictions on modulation mode, spatial stream and RU, and is only suitable for transmitting services with lower data rates. With the emergence of various application scenarios, such as VR/XR, this method cannot be used in situations where services with large amounts of data require high-reliability transmission.

Summary of the invention

The purpose of the embodiments of the present invention is to provide a modulation and coding strategy selection method, device, terminal and storage medium, so that in the case of long-distance transmission, it can not only meet the gradually increasing data transmission requirements, but also ensure that the coverage is wide enough and the data transmission rate is not reduced due to the influence of the long distance. Under the condition of the same transmission power, it not only expands the coverage of the Wi-Fi access point, so that the terminals far away from the access point can communicate normally, but also ensures that the data transmission rate is fast enough and reliable enough.

To solve the above technical problems, an embodiment of the present invention provides a modulation and coding strategy selection method, including: when the distance between the access point and the access point exceeds a preset distance, restricting some features in the modulation and coding strategy table; when the distance between the access point and the access point exceeds the preset distance, after selecting the modulation and coding index in the modulation and coding strategy table based on the restricted partial features 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; wherein restricting some features in the modulation and coding strategy table includes: restricting some rows in the modulation and coding strategy table, and all parameters in the restricted rows enter an unavailable state; and/or, restricting the number of spatial streams in the modulation and coding strategy table so that some working modes cannot be configured as an enabled state.

An embodiment of the present invention also provides a modulation and coding strategy selection device, including: a feature restriction module, which is used to restrict some features in the modulation and coding strategy table when the distance between the access point exceeds a preset distance; a margin correction module, which is used to select a modulation and coding index in the modulation and coding strategy table based on the restricted part of the 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 when the distance between the access point exceeds the preset distance; wherein restricting some features in the modulation and coding strategy table includes: restricting some rows in the modulation and coding strategy table, and all parameters in the restricted rows enter an unavailable state; and/or limiting the number of spatial streams in the modulation and coding strategy table so that some working modes cannot be configured as an enabled state.

An embodiment of the present invention also provides 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, and the instructions are executed by the at least one processor so that the at least one processor can execute the above-mentioned modulation and coding strategy selection method.

An embodiment of the present invention further provides a computer-readable storage medium storing a computer program, which implements the above-mentioned modulation and coding strategy selection method when executed by a processor.

In an embodiment of the present invention, when the distance from 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 enter an unavailable state; and/or, the number of spatial streams in the modulation and coding strategy table is restricted so that some working modes cannot be configured as enabled states. After selecting the modulation and coding index in the modulation and coding strategy table based on the restricted partial features 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 advantage of this is that, under the same transmission power, the coverage of the access point is expanded, so that terminals far away from the access point can communicate normally, and the data transmission rate is guaranteed to be fast enough. In the case of long-distance transmission, it can not only meet the gradually increasing data transmission requirements, but also ensure that the coverage is wide enough and the data transmission rate is not reduced due to the influence of the long distance.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

FIG1 is a flow chart of a modulation and coding strategy selection method provided according to an embodiment of the present invention;

2 is a flow chart of a modulation and coding strategy negotiation initiated by an access point according to an embodiment of the present invention;

3 is a flowchart of a terminal initiating modulation and coding strategy negotiation according to an embodiment of the present invention;

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

FIG5 is a schematic diagram of the structure of a terminal according to another embodiment of the present invention.

DETAILED DESCRIPTION

To make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in the embodiments of the present invention, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can be implemented. The division of the following embodiments is for the convenience of description, and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined and referenced with each other without contradiction.

An embodiment of the present invention relates to a modulation and coding strategy selection method, which can be applied to any terminal device that can be wirelessly connected to an access point, such as a mobile phone, a computer 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 enter an unavailable state; and/or, the number of spatial streams in the modulation and coding strategy table is restricted so that some working modes cannot be configured as enabled states. After selecting a modulation and coding index in the modulation and coding strategy table based on the restricted partial features 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 this is that, under the same transmission power, the coverage of the access point is expanded, so that terminals far away from the access point can communicate normally, and the data transmission rate is ensured to be fast enough and reliable enough. In the case of long-distance transmission, it can not only meet the gradually increasing data transmission requirements, but also ensure that the coverage is wide enough and the data transmission rate is not reduced due to the influence of the long distance. The implementation details of the modulation and coding strategy selection method of this embodiment are specifically described below. The following content is only the implementation details provided for easy understanding and is not necessary for implementing this solution.

As shown in Figure 1, in step 101, 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; wherein, restricting some features in the modulation and coding strategy table can be: restricting some rows in the modulation and coding strategy table, and all parameters in the restricted rows enter an unavailable state, or restricting the number of spatial streams in the modulation and coding strategy table so that some working modes cannot be configured as an enabled state.

Some parts of the restriction table are due to the consideration that in some scenarios, it is necessary to ensure the coverage of the access point (AP) over a long distance, or other requirements, such as increasing the reliability of the Wi-Fi signal to support certain special terminals. At this time, it is not possible to select the modulation coding index (MSCindex) for the purpose of maximizing spectrum efficiency or minimizing BER. When a terminal is far away from the access point, it can be more inclined to select a lower modulation order and a lower coding rate. This is because selecting a lower modulation order allows the terminal or access point to still demodulate correctly when receiving a signal with a lower signal-to-noise ratio. On the other hand, a lower coding rate also gives the terminal or access point a stronger error correction capability. As we all know, erroneous bits are prone to occur when the signal-to-noise ratio is low. Selecting a lower coding rate can just deal with this problem. In order to ensure the long-distance coverage of the AP terminal or increase the reliability of the Wi-Fi signal, it can be achieved by retaining a part of the SNR margin when selecting the MCS index, or by setting some MCSindex in the MSC table in the standard to be unavailable. The effect of the two working together is better, which is not difficult to see from the above. It is quite effective to restrict some features in the modulation and coding strategy table.

In one example, limiting some features in the modulation and coding strategy table may be limiting certain rows of the MCS table of a certain resource unit (RU), so that these restricted rows cannot be used. The MCS table of the RU is similar to Table 1 above. The restriction can also be applied to the MCS tables of other types of resource units, which will not be listed one by one in this article. In some cases, the restricted rows have common modulation modes, such as QAM-1024, or common coding rates such as 5/6. In some cases, certain rows of the restriction contain certain protection intervals (GI for short, full name guard interval), that is, after being restricted, these GIs and their corresponding transmission rates will be unavailable.

In one example, limiting some features in the modulation and coding strategy table can also make some frame formats of terminals far away from the access point unavailable or disabled. For example, a multi-user send request (MU-RTS) trigger frame. Or multi-user-multiple-input-multiple-output (MU-MIMO) transmission is not supported, that is, uplink MU-MIMO transmission is not supported or downlink MU-MIMO transmission is not supported. A better coverage effect has been achieved. Because MU-MIMO transmission requires better spatial isolation, in order to avoid interference from other users in the same group, in one example, the terminal does not support MU-MIMO transmission.

In one example, limiting some features in the modulation and coding strategy table can be by limiting some parameters and thus limiting the working mode of the terminal device. For example, in some cases, the terminal does not support multi-data stream transmission, such as not supporting more than 2 data stream transmission. Similar data stream transmission also requires better spatial isolation. Because the terminal is far away from the associated access point, the spatial isolation cannot reach the ideal state, so the number of supported spatial streams needs to be limited. For example, if a terminal is far away from the access point (for example, greater than 500m), some working modes cannot be enabled or the working mode will not be configured to be enabled, such as limiting the number of spatial streams to no more than 2. Limit the number of spatial streams in the modulation and coding strategy table so that some working modes cannot be configured to be enabled. Or, for example, limit the number of transmitting or receiving antennas to no less than two. Since multiple antennas transmit and the signal energy is high, this restriction can enable the terminal device to better use spatial diversity.

In one example, when the distance between the terminal device and the access point exceeds the preset distance, the size, type, and occupied bandwidth of the resource unit can be restricted; there are various ways to restrict the resource unit. For example, in some cases, the terminal far from the access point can be restricted from supporting the use of smaller RUs (such as RUs with less than 106 carriers). In some cases, the terminal far from the access point can be restricted to only support the use of regular RUs. In some cases, the terminal far from the access point can be restricted to only support the use of distributed RUs. This is a newly defined RU, in which the carrier resources in the RU are interwoven with other RUs of the same type in the OFDM symbol frequency domain. In some cases, the terminal far from the access point does not support the use of RUs with a bandwidth greater than a certain bandwidth. For example, some RUs (resource units) or MRUs (multiple resource units) with a bandwidth greater than 20MHz, 40MHz, or 80MHz. Among them, the RU is a regular RU or a distributed RU. In some cases, due to the amount of terminal data and other reasons, a larger RU is not used to avoid using more energy for transmission. In some cases, terminals far from the access point do not support the use of RUs with bandwidths less than a certain value. For example, when using dRUs, frequency domain diversity benefits can only be obtained if the bandwidth occupied by the dRUs is large enough. For example, some RUs or multiple resource units (MRUs) occupy bandwidths greater than 20MHz, 40MHz, or 80MHz.

In one example, when the distance from the access point exceeds the 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 be greater than the preset frequency; for example, in some cases, the terminal cannot use a bandwidth exceeding a certain bandwidth for data transmission. For example, when the terminal is far away from the associated AP, greater than 200 meters, it cannot use a bandwidth exceeding 80MHz for data transmission. One possibility is that the power consumption of the terminal is relatively high when it is far away from the AP, and a relatively narrow bandwidth needs to be used for transmission.

In one example, when the distance between a terminal device and an access point exceeds a preset distance, the size of the transmitted data packet is limited so that the size of the transmitted data packet shall not be larger than the preset data packet size; for example, in some cases, a terminal that is far away from the access point does not support, or is configured not to transmit, data packets larger than a certain size.

In one example, when the distance from the access point exceeds a preset distance, the type of data packet transmitted is restricted. For example, in some cases, a terminal far away from the access point does not support or is configured not to transmit certain types of data packets, such as the following types: TB (trigger-based) PPDU, SU (SingleUser) PPDU, or MU-PPDU (Multi-User Physical layer Protocol Data Unit). Or only HE/EHT/UHR ER SU PPDU can be transmitted. HE/EHT/UHR stands for high efficiency (HE for high efficiency), Extremely high efficiency (EHT for high efficiency), and ultra high reliability (EHT for ultra high reliability), respectively, representing the core features of Wi-Fi 6, Wi-Fi 7, and Wi-Fi 8.

The above restrictions do not conflict with each other and can be freely selected according to actual needs. In one example, the above method is limited to being effective in at least one domain, or at least one field, or frame body, or frame header in a frame format. Specifically: In some cases, the above restrictions and the margin adjustment mentioned below all act on at least one domain (field) in a frame format, that is, only work on at least one domain (field) in a frame format, or at least one field in a frame format, or the frame body in a frame format, or the frame header in a frame format. For example, the HE/EHT/UHR SU PPDU includes L-STF (Legacy Short Training Field), L-LTF (Legacy Long Training Field), L-SIG (Legacy Signal Field), RL-SIG (a repeated legacy signal field), HE-SIG-A (an efficient signal field), HE-STF (an efficient short training field), HE-LTF (an efficient long training field), data (a data field), and PE (a header field). The above restrictions and margin adjustments only apply to at least one of the fields (filed), such as data. Similarly, in HE/EHT/UHR MUPPDU, or HE/EHT/UHR TB PPDU, or HE/EHT/UHR ER SU PPDU, the above restrictions can be applied to at least one field in the corresponding frame.

In some cases, restricted features, such as certain rows in the MCS table, or parameters in the working mode, such as spatial streams. The parameter, or restriction, is contained in a newly defined frame, or a trigger frame. The access point transmits it to the terminal through a trigger frame to notify the terminal. In some cases, a newly defined frame or trigger frame contains a margin, or the type of frame that is restricted, or the type of frame that is allowed to be transmitted. Or it contains the above-mentioned restriction, or margin, the type of frame that is effective, or the type of frame that is effective, and the field that is effective in the type frame.

In one example, in some cases, resource units may be restricted using restrictions similar to <HE-MCS 0,1>. For example, <EHT-MCS a,b> where a,b are positive integers a>2, and a<5, b>1, b<4. For example, <UHR-MCS c,d> where c,d where c>2, and c<5, d>1, d<4. Variables a, b, c, d are restricted to different ranges. The specific ranges here are for illustration only and are not absolute regulations.

In one example, in some cases, the device needs to use beamforming for transmission. For example, the terminal device is far away from the AP and needs to use beamforming for downlink transmission. There is no beamforming transmission method for uplink transmission at present. Considering that the AP has a strong ability to detect uplink signals, no restriction is made here.

In one example, parameter restriction occurs and is related to the distance between the terminal device and the access point. For example, if the terminal is close to the AP, it can be restricted to transmit smaller data packets to avoid frequent channel preemption by other terminals, or use more moderate enhanced distributed channel access (EDCA) parameters. If the terminal is far away from the AP, a more aggressive EDCA parameter preemption method can be used. In some cases, the distance from the AP is distinguished by one or more thresholds. For example, less than 50 meters is close to the AP, or more than 100 meters is far from the AP. In some cases, the EDCA type is restricted, such as using a smaller contention window or a longer TXOP (transmission opportunity) duration when a distant terminal accesses.

In step 102, when the distance between the terminal 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 part feature 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 a modulation and coding index margin;

The modulation coding index margin here can also be called MCS index offset, or MCS index offset, or MCS index difference. Regardless of the name, it indicates the difference between the MCS index actually applied and the MCS index obtained through channel measurement. Here, Table 1 is taken as an example. Other MCS tables are similar to it and have their corresponding MCS index offsets, which will not be repeated.

For ease of understanding, an example is given here. In one example, for a certain terminal, the MCS index (MCS index) has an offset (also referred to as the modulation coding index margin), taking Table 1 as an example. Some large MCS indexes will not be available. The MCS index selected according to the general method is the first modulation coding index, and an offset is required (i.e., minus 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. At the same time, the MCS index obtained by measuring the channel is the modulation coding index value in Table 1, which is the first modulation coding index (to avoid confusion, it is also referred to as EHT-MCS index). Afterwards, the first modulation coding index is corrected to the second modulation coding index, that is, the EHT-MCS index is retracted to EHT-MCS index-ΔX. EHT-MCS index-ΔX is used as the modulation coding index value corresponding to Table 1 for modulation coding transmission information. For example, the modulation coding index in Table 1 corresponding to 10% BLER or maximizing spectral efficiency calculated by channel measurement SNR, etc. is 10. Thereafter, by using the modulation coding index margin ΔX=2, the modulation coding index applied during data transmission is 8.

Through the design of the margin, when transmitting to some terminals far away from the access point, for example, it is determined through simulation that the threshold for selecting the MCS index is not the traditional 10% BER, or the corresponding signal-to-noise ratio threshold at BLER. Instead, it is 5% BER, or the corresponding signal-to-noise ratio threshold at BLER. At this time, the access point has to select a lower modulation order or a lower coding rate for the long-distance terminal. From another perspective, when selecting the MCS index, the signal-to-noise ratio margin comparison makes the BLER and BER of the original MCS index without margin reach 5% BLER and BER at this time. In some cases, the margin may not accurately reduce the BLER or BER to 5%, but may also be other values, such as 8%, 7%, or 4%.

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, which can be: 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, so as to correct the first modulation coding index to the second modulation coding index. The corresponding relationship and setting of the margin are various, and the following will discuss this with examples in turn:

In some cases, the MCS index corresponding to each RU has only one common margin ΔX. For example, in the above case, it is 2. The margin can be other positive integer values. The margin ΔX of the MCS index of each RU is different from the MCSindex margin ΔX of another RU.

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

In some cases, each RU's MCS index has multiple margins ΔX, or at least one margin. The at least one margin is obtained through simulation or is configurable. In this case, the margin exists in the form of a vector or an array.

In some cases, the margin ΔX of the MCS index of each RU is at least one (or a group). The margin value is bound to the service type. For example, at least one ΔX for video services, at least one ΔX for voice services, at least one ΔX for low-latency services, and at least one ΔX for other services.

In some cases, all MCS indexes of the same RU have a common margin ΔX, such as 2 in the above case. The margin can be other positive integer values.

In some cases, the MCS indexes of all RUs have a common margin ΔX, such as 2 in the above case. The margin can be other positive integer values.

In one example, using margin to correct the modulation coding index is a mode that is turned on for certain situations. As long as the triggering conditions are met, the margin mode can be turned on for adjustment. By using the modulation coding index margin, the first modulation coding index is corrected to the second modulation coding index. It can be: when the specified parameter information meets the corresponding preset restriction conditions, the margin mode is turned on, so that the first modulation coding index is corrected to the second modulation coding index by using the modulation 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. The possibilities of triggering conditions for turning on the margin mode are far more than that. The following are some examples of possible situations:

In some cases, when a terminal meets a certain distance from its associated access point, the MCS index offset mode is automatically started. In some cases, the distance is a threshold, which is configurable, or the threshold is determined at the factory. In some cases, the threshold is related to the carrier frequency of the channel, for example, the higher the frequency, the smaller the threshold. In some cases, starting the MCS index offset mode is transparent to the terminal, and all MCS calculations and selections occur at the access point.

In some cases, this margin mode only works for narrowband terminals, such as some terminals with a bandwidth of 20MHz or some terminals with a bandwidth of 40MHz. It does not work for terminals with a working bandwidth greater than this bandwidth.

In some cases, the margin mode only works for certain services, such as video services or voice services. In some cases, the MCS index margin mode of the current terminal is bound to the service. When the terminal transmits certain service modes,

In some cases, the margin mode only works on certain frequency bands, or frequency bands, such as 2.4GHz.

In some cases, the margin mode works only on certain connections, such as when the terminal is a multi-connection device.

In some cases, the margin mode works on a channel frequency (2.4GHz or 5GHz, or 6GHz), works on a bandwidth, or works on a service, or works on a terminal type (Wi-Fi 7 terminal, or Wi-Fi 6 terminal, or Wi-F 8 terminal, or other terminal), or works on a connection, at least one of which is configurable. The specific configuration signaling is included in a control frame or a trigger frame. In some cases, the service it works on is a low-latency service.

In some cases, the margin mode is automatically activated by identifying the terminal's MAC address, and when it is within a certain range, or contains a certain field, such as a MAC address identifier belonging to a certain manufacturer, the margin mode is automatically activated.

In some cases, the margin mode is automatically activated by identifying the MAC address of the terminal, when it is within a certain range, or contains a certain field, such as a MAC address identifier belonging to a certain manufacturer, and when the terminal is greater than a certain threshold from the associated access point, the margin mode is automatically activated.

In some cases, the margin mode is automatically activated by identifying the MAC address of the terminal, and when the terminal is within a certain range and the distance from the associated access point is greater than a certain threshold, the margin mode is activated through a control frame or a trigger frame.

The configuration of margin mode does not conflict with the above-mentioned means of limiting features, and can be performed separately or together. For example, when the above-mentioned feature restriction only works on certain connections, margin mode is enabled.

In one example, the headroom mode can be automatically exited. When the connection with the access point is disconnected, the headroom mode is automatically exited. When a frame carrying headroom mode release information sent by the access point is received, the headroom mode is exited. There are various ways to end the headroom mode. The following are some examples of possible situations:

In some cases, if the current terminal operates in the MCS index margin mode, the MCS margin mode is automatically terminated when the terminal leaves the current access point.

In some cases, if the current terminal is working in the MCS index margin mode, it enters the current margin working mode due to service changes, or the arrival of new services such as (VR/XR services), or low-latency services. According to the maximum throughput or the highest spectrum efficiency, the MCS index is selected to schedule the current service.

In some cases, the access point transmits a control frame, a negotiation frame, a broadcast frame, or a notification frame to include the headroom mode termination information. In some cases, the headroom mode termination is one-to-one, such as the access point transmitting the information to a certain terminal. In some cases, the headroom mode termination is multicast or broadcast, and the access point notifies at least one terminal of the headroom mode termination by transmitting the above frame.

In one example, a terminal supporting surplus transmission joins a group, and the members of the group join the group by negotiating with the access point. In the group, the terminals in the group are notified to turn on or off the surplus mode through control frames, negotiation frames, broadcast frames, or notification frames, etc. The control frame, negotiation frame, broadcast frame, or notification frame, etc. contain a group ID, a group identifier, or a group number. It is used to determine that the terminal belongs to a specific group. That is, the surplus mode release information contains the group identifier of the surplus mode group, and the surplus mode group is formed by multiple terminals connected to the same access point and supporting the opening of the surplus mode through negotiation with the access point.

In one example, an RU determines the margin or characteristic limit of the MCS index, which is a pattern or a set of data used to indicate the various limits. The margin or limit corresponds to a Wi-Fi 6 terminal or a Wi-Fi 7 or a Wi-Fi 8 terminal. The pattern or a set of data is stored in the access point or the terminal at the factory (or at the time of manufacturing) and is numbered. The access point transmits the number through certain frames to complete the configuration of the terminal. The advantage of the method is that there is no need to transmit specific data, which saves air interface data transmission. The frame can be a configuration reserved for certain frames, or a bit, indicating the MCS index margin, or certain limits.

In one example, a certain fragment of data is repeatedly transmitted, and the repeatedly transmitted data is merged on the receiving device side to increase the signal-to-noise ratio and achieve the purpose of coverage enhancement. That is, when the sending side sends data, the data is repeatedly sent; when the receiving side receives the repeated data, the repeated data is merged. For example, some protocol data units (Presentation Protocol Data Unit, referred to as PPDU) are repeatedly transmitted.

In some cases, some PPDUs are repeatedly transmitted in the frequency domain, time domain, or spatial domain (on spatial stream), or a part of some PPDUs, such as the data field, or some types of PPDUs are repeatedly transmitted, or a part of some types of PPDUs (such as the data field) are repeatedly transmitted. For example, within a PPDU, a part of the data is repeatedly transmitted on the data field. The original data and the repeatedly transmitted data are both included in the data field.

In some cases, repeated transmission is performed on RU (resource unit). For example, the same content is repeatedly transmitted on the same RU, or the same content is repeatedly transmitted on different RUs. The method of retransmission can use the method mentioned above. Among them, the same content is transmitted on different RUs, including MRU (multiple RU, multiple resource unit) scheduling, such as scheduling two RUs at the same time, and the sizes of the two RUs are the same. The content transmitted on RU1 is consistent with the content transmitted on RU2. Among them, the case of repeated transmission within one RU, the case of repeated transmission within multiple RUs, or the case of regular RU (regular RU) and distributed RU (distributed RU). In multi-RU transmission, the two RUs used for repeated transmission are both regular RUs, or both RUs are distributed RUs, or one RU is a regular RU and the other RU is a distributed RU.

Repeated transmission within one RU or on multiple RUs. Time domain repeated transmission can be used, that is, repeated transmission over a long period of time. For example, at time t1, the data is on a part of the carriers within an RU, or on all the carriers of an RU; at time t2, the repeatedly transmitted data is on another part of the carriers of the RU, or on another RU in multi-RU transmission. Frequency domain repeated transmission means that at the same time, the data and the repeatedly transmitted data are transmitted on different carriers within an RU, or on different RUs when multi-RU scheduling is used.

Next, we will discuss the indication method of repeated transmission. In some cases, a frame is transmitted by the access point to indicate or inform the terminal of the specific method of repeated transmission. The frame can be an initial control frame, a trigger frame, or a negotiation frame, or a newly defined negotiation frame for repeated transmission. The frame contains a specific indication of the repeated transmission method, such as the repeated transmission method mentioned above, repeated transmission within an RU. For example, it indicates the repeated transmission of a part of the content of a certain type of data frame. In some cases, the frame contains a field to indicate whether to repeat the transmission of the entire frame or a part of the frame (data field).

In one example, the data interaction when the modulation and coding strategy selection is initiated by the access point is shown in FIG2. The access point determines the parameter range, component mode, or repeated transmission mode of the terminal based on its own judgment of the terminal. If the notification of the access point is not broadcast, the terminal sends an acknowledgment character (ACK for short, full name Acknowledge character) after receiving the notification, otherwise it does not send. The data interaction when the modulation and coding strategy selection is initiated by the access point is shown in FIG3. The access point determines the parameter range, component mode, or repeated transmission mode of the terminal based on the status (position) reported by the terminal or the request information of the terminal. If the notification of the access point is not broadcast, the terminal sends ACK after receiving the notification, otherwise it does not send. In some cases, the notification is included in the trigger frame. After receiving the trigger frame, the terminal receives the data frame according to the trigger frame instruction, and then sends ACK, or batch ACK. In some cases, after receiving the trigger frame, the terminal sends uplink data according to the trigger frame instruction.

In some cases, the notification frame may be an initial control frame, a trigger frame, a negotiation frame, or a newly defined frame for configuring the terminal parameter range or working mode. In some cases, after receiving the notification frame, the terminal does not execute the parameter limit, margin, or repeated transmission mode in the notification frame. The notification frame is only a suggestion. The terminal feeds back its execution status in the ACK frame, for example, only executing the parameter repeated transmission mode.

In some cases, after receiving the notification frame, the terminal needs to execute the parameter limit, margin, or repeated transmission mode in the notification frame. The notification frame signaling is a request for execution. The terminal gives feedback on its execution status in the ACK frame. Or it is assumed that the terminal must execute. The signaling of the notification frame, or the command content, does not need to be confirmed again in the ACK. The role of ACK is only to confirm the receipt of the notification frame.

In some cases, the notification frame is accompanied by uplink or downlink data transmission that meets the requirements of the notification frame content. After that, the receiver sends an ACK to the data sender when the data is correctly received. Otherwise, the receiver of the data does not transmit an ACK.

In some cases, the access point and the terminal do not need to negotiate the data transmission shown in Figures 2 and 3, and the above-mentioned restriction or margin mode or repeated transmission mode is directly turned on, for example, the signal-to-noise ratio obtained by measuring the channel meets the higher modulation mode, but deliberately indicates and uses a lower signal-to-noise ratio to ensure transmission robustness. Or as shown above, when the distance between the terminal and the access point is greater than a certain threshold, the restriction, margin mode, or repeated transmission mode is automatically started.

In some cases, a negotiation method similar to that shown in FIG3 is used, where the AP sends an MRQ (MRQ is short for MFB requester, MFB is short for MCS feedback) to the terminal, and the terminal transmits the MFB to the AP. The AP decides the data frame parameters and format for the next downlink transmission based on its own situation. In some cases, the AP and the base station reuse the MCS feedback mechanism to determine the MSC index or other parameter limits listed above based on the terminal's suggestion.

In some cases, the above-mentioned method of limiting certain characteristics of the data transmission step, or the method of MCS index margin, or the method of repeated transmission, is applied to multicast frames other than beacon frames.

In some cases, the above restrictions, such as bandwidth, spatial stream, PPDU type, are included in the transmit vector (TxVector) or receive vector (RxVector), transmitted to the terminal or AP through control frames, or MFQ, MFB. Or included in the UHR capability element (UHR capability element, where UHR is the abbreviation of Ultra High Reliable, meaning ultra-high reliability) or in the PHY capability element (PHY capability element, where PHY means physical layer).

In this embodiment, when the distance between the terminal device and the access point exceeds the 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 enter an unavailable state; and/or, the number of spatial streams in the modulation and coding strategy table is restricted so that some working modes cannot be configured as enabled states. After selecting the modulation and coding index in the modulation and coding strategy table based on the restricted partial features 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 advantage of this is that, under the same transmission power, the coverage of the access point is expanded, so that the terminals far away from the access point can communicate normally, and the data transmission rate is guaranteed to be fast enough. In the case of long-distance transmission, it can not only meet the gradually increasing data transmission requirements, but also ensure that the coverage is wide enough and the data transmission rate is not reduced due to the influence of the long distance.

The steps of the above method are divided only for clear description. When implemented, they can be combined into one step or some steps can be split and decomposed 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 to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this application.

Another embodiment of the present invention relates to a modulation and coding strategy selection device, as shown in Figure 4, including: a feature restriction module 401, which is used to restrict some features in the modulation and coding strategy table when the distance between the access point exceeds a preset distance; a margin correction module 402, which is used to select a modulation and coding index in the modulation and coding strategy table based on the restricted part of the 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 when the distance between the access point exceeds the preset distance; wherein restricting some features in the modulation and coding strategy table includes: restricting some rows in the modulation and coding strategy table, and all parameters in the restricted rows enter an unavailable state; and/or, limiting the number of spatial streams in the modulation and coding strategy table so that some working modes cannot be configured as an enabled state.

In one example, the device also includes: a resource limitation module, which is used to limit the size, type, and occupied bandwidth of the resource unit when the distance from the access point exceeds a preset distance; and/or, when the distance from the access point exceeds a preset distance, limit the frequency of the bandwidth used when transmitting data, so that the frequency of the bandwidth used when transmitting data cannot be greater than the preset frequency; and/or, when the distance from the access point exceeds a preset distance, limit the size of the transmitted data packet, so that the size of the transmitted data packet cannot be greater than the preset data packet size; and/or, when the distance from the access point exceeds a preset distance, limit the type of the transmitted data packet.

In one example, the functions performed by the modules of the apparatus are limited to at least one domain, or at least one field, or at least the frame body, or the frame header in a frame format.

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, so as to correct the first modulation coding index to the second modulation coding index.

In one example, a first modulation coding index is corrected to a second modulation coding index by using a modulation coding index margin, including: when the specified parameter information meets the corresponding preset restriction condition, a margin mode is turned on to correct the first modulation coding index to a second modulation coding index by using the modulation coding index margin in the margin mode; wherein the specified parameter information includes one of the following or any combination thereof: a bandwidth type corresponding to the terminal, a service type processed by the terminal, a channel frequency corresponding to the terminal, and a connection type corresponding to the terminal.

In one example, the device also includes: a headroom mode switching module, which is used to automatically exit the headroom mode when disconnected from the access point; and exit the headroom mode after receiving a frame sent by the access point carrying headroom mode release information; wherein the headroom mode release information includes a group identifier of a headroom mode group, and the headroom mode group is formed by multiple terminals connected to the same access point and supporting the activation of the headroom mode through negotiation with the access point.

In one example, the device further includes: a repeated transmission module, which is used to repeatedly send the data when sending data as a sending side; and merge the repeated data after receiving the repeated data as a receiving side.

In this embodiment, when the distance between the terminal device and the access point exceeds the 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 enter an unavailable state; and/or, the number of spatial streams in the modulation and coding strategy table is restricted so that some working modes cannot be configured as enabled states. After selecting the modulation and coding index in the modulation and coding strategy table based on the restricted partial features 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 advantage of this is that, under the same transmission power, the coverage of the access point is expanded, so that the terminals far away from the access point can communicate normally, and the data transmission rate is guaranteed to be fast enough. In the case of long-distance transmission, it can not only meet the gradually increasing data transmission requirements, but also ensure that the coverage is wide enough and the data transmission rate is not reduced due to the influence of the long distance.

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

It is worth mentioning that all modules involved in this embodiment are logic modules. In practical applications, a logic unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by the present invention, but this does not mean that there are no other units in this embodiment.

Another embodiment of the present invention relates to a terminal, as shown in Figure 5, comprising 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, and the instructions are executed by the at least one processor 501 so that the at least one processor 501 can execute the modulation and coding strategy selection method as described above.

The memory 502 and the processor 501 are connected in a bus manner, and the bus may include any number of interconnected buses and bridges, and the bus connects various circuits of one or more processors 501 and the 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 are therefore not further described herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be one element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices on a transmission medium. The data processed by the processor 501 is transmitted on a wireless medium via an antenna, and further, the antenna also receives data and transmits the data to the processor 501.

The 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. The memory 502 can be used to store data used by the processor 501 when performing operations.

Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

That is, those skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions to enable a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims (10)

1. A method for selecting a modulation and coding strategy, comprising: When the distance to the access point exceeds a preset distance, some features in the modulation and coding strategy table are restricted; When the distance to 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 portion feature 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 a modulation and coding index margin; Among them, some features in the modulation and coding strategy table are restricted, including: Restricting some rows in the modulation and coding strategy table, so that all parameters in the restricted rows enter an unavailable state; and/or, The number of spatial streams in the modulation and coding strategy table is limited so that some working modes cannot be configured as enabled states. 2. The method for selecting a modulation and coding strategy according to claim 1, characterized in that the method further comprises: When the distance from the access point exceeds a preset distance, the size, type, and occupied bandwidth of the resource unit are restricted; and/or, When the distance between the access point and the access point exceeds a preset distance, limiting the frequency of the bandwidth used for data transmission so that the frequency of the bandwidth used for data transmission cannot be greater than the preset frequency; and/or, When the distance between the access point and the access point exceeds a preset distance, limiting the size of the transmitted data packet so that the size of the transmitted data packet shall not be larger than the preset data packet size; and/or, When the distance between the access point and the access point exceeds a preset distance, the type of the transmitted data packet is restricted. 3. The modulation and coding strategy selection method according to any one of claims 1 to 2 is characterized in that the method is limited to being effective on at least one domain in a frame format, or at least one field, or at least the frame body, or the frame header. 4. The method for selecting a modulation and coding strategy 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 modifying the first modulation and coding index to a second modulation and coding index by using the modulation and coding index margin comprises: When the first modulation coding has a plurality of the 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, so as to correct the first modulation coding index to the second modulation coding index. 5. The method for selecting a modulation and coding strategy according to claim 1, wherein the step of correcting the first modulation and coding index to a second modulation and coding index by using a modulation and coding index margin comprises: When the specified parameter information satisfies the corresponding preset restriction condition, a margin mode is enabled, so as to modify the first modulation coding index to a second modulation coding index by using the modulation coding index margin in the margin mode; 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. 6. The method for selecting a modulation and coding strategy according to claim 5, characterized in that the method further comprises: When disconnected from the access point, automatically exiting the margin mode; After receiving a frame carrying margin mode release information sent by the access point, exiting the margin mode; The headroom mode release information includes a group identifier of a headroom mode group, and the headroom mode group is formed by a plurality of terminals connected to the same access point and supporting the headroom mode activation through negotiation with the access point. 7. The method for selecting a modulation and coding strategy according to claim 1, characterized in that the method further comprises: When sending data as a sending side, repeatedly sending the data; After serving as the receiving side and receiving the repeated data, the repeated data are merged. 8. A modulation and coding strategy selection device, characterized in that it comprises: A feature restriction module, used to restrict some features in the modulation and coding strategy table when the distance to the access point exceeds a preset distance; a margin correction module, configured to, when the distance to the access point exceeds a preset distance, select a modulation and coding index in the modulation and coding strategy table based on the restricted part feature to obtain a first modulation and coding index, and correct the first modulation and coding index to a second modulation and coding index by using a modulation and coding index margin; Among them, some features in the modulation and coding strategy table are restricted, including: Restricting some rows in the modulation and coding strategy table, so that all parameters in the restricted rows enter an unavailable state; and/or, The number of spatial streams in the modulation and coding strategy table is limited so that some working modes cannot be configured as enabled states. 9. A terminal, comprising: at least one processor; and, 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, and the instructions are executed by the at least one processor to enable the at least one processor to execute the modulation and coding strategy selection method as described in any one of claims 1 to 7. 10. A computer-readable storage medium storing a computer program, characterized in that when the computer program is executed by a processor, the modulation and coding strategy selection method according to any one of claims 1 to 7 is implemented.