A method for adaptive modulation and coding of carrier communication and computer storage medium

Abstract

The invention discloses a method for adaptive modulation and coding of carrier communication and a computer storage medium, the steps comprising: estimating the signal-to-noise ratio of each pilot subcarrier in the pilot symbol according to the frequency domain received signal of each subcarrier in the pilot symbol, taking the proportion of the signal-to-noise ratio of each pilot subcarrier in the total pilot subcarrier as the weight of the corresponding pilot subcarrier under the influence of the channel; obtaining a calibration factor according to the weight of each pilot subcarrier; obtaining a reference signal-to-noise ratio by using the variance of the signal-to-noise ratio of the pilot subcarrier, the calibration factor and the mean value of the signal-to-noise ratio of the pilot subcarrier, and switching the adaptive modulation and coding transmission mode by using the reference signal-to-noise ratio to avoid the problem that the signal-to-noise ratio error is large, the bit error rate is high, and the communication reliability and communication efficiency are relatively low.

Description

Technical Field

[0001] The invention relates to communication technology, in particular to a carrier communication adaptive modulation coding method and a computer storage medium. Background Art

[0002] Due to the influence of interference factors such as single tone, pulse and noise, the power line carrier communication channel is complex and changeable. In order to ensure the communication quality to the greatest extent and improve the spectrum efficiency of the system, the research on the real-time optimization of the channel has important practical significance.

[0003] In the system, if a fixed modulation and coding scheme (MCS) is used, its block error rate (BLER) will fluctuate greatly as the channel changes. This is not conducive to the system achieving the maximum network throughput, and it cannot well guarantee the link communication quality. Adaptive coding and modulation (ACM) can dynamically track channel changes and adaptively select modulation and coding schemes according to channel conditions (SNR, BLER of received signals, etc.), so it can maximize the system throughput and ensure the target block error rate. At present, the research on ACM technology mainly focuses on mode selection methods, channel coding improvements, accurate channel quality capture and ACM implementation. Among them, the selection of modulation and coding strategy (MCS) is the core part of ACM technology. In order to ensure the reliability and timeliness of information transmission in the link, the signal-to-noise ratio (SNR) can be selected as a measure of channel quality, and the modulation, coding and data rate that meet specific requirements can be selected to finally form a specific MCS type combination, and the available communication channel resources can be fully utilized to adapt the MCS type and data transmission rate to the communication channel environment conditions. The characteristic of the ACM system that changes the transmission scheme as the channel quality changes determines that the channel quality estimation error is a very important issue.

[0004] The basic idea of ​​ACM technology is to improve system throughput and spectrum utilization and reduce system overhead by adjusting input parameters such as coding and modulation mode without sacrificing block error rate. When the transmitter sends data, the selected modulation coding transmission mode is usually determined by the signal-to-noise ratio interval of the channel signal-to-noise ratio (SNR) estimation result. If the receiving signal-to-noise ratio based on which the adaptive transmission mode is selected does not take into account the interference caused by force majeure factors such as channel estimation error, the selected transmission mode parameters will not match the actual channel quality, resulting in system performance deterioration. For example, a Chinese patent application document with publication number CN104468032A discloses an adaptive modulation coding beam switching method for a mobile broadband satellite communication system applied to high-speed railways. This method is also a method for determining the state of adaptive modulation coding. In this method, the signal-to-noise ratio is calculated by the average signal-to-noise ratio of each subcarrier, and the correction of the signal-to-noise ratio is based on the average signal-to-noise ratio and multiplied by a fixed parameter. The obtained signal-to-noise ratio cannot reflect the actual channel quality, thereby affecting the selected coding transmission mode, reducing the system throughput and spectrum utilization of the system, and affecting the performance of the system. Summary of the invention

[0005] The purpose of the present invention is to provide a method for adaptive modulation coding of carrier communication and a computer storage medium, which is used to solve the problem in the prior art that the error between the signal-to-noise ratio estimation result and the actual signal-to-noise ratio is large, resulting in the selected coding transmission mode being unsuitable for the current transmission situation, causing the communication reliability and communication efficiency to be relatively low.

[0006] In order to solve the above technical problems, the present invention provides a method for carrier communication adaptive modulation and coding, the steps comprising:

[0007] The signal-to-noise ratio of each pilot subcarrier in the pilot symbol is estimated according to the frequency domain received signal of each subcarrier in the pilot symbol, and the proportion of the signal-to-noise ratio of each pilot subcarrier in the total pilot subcarriers is used as the weight of the corresponding pilot subcarrier under the influence of the channel; the calibration factor is obtained according to the weight of each pilot subcarrier; the reference signal-to-noise ratio is obtained by using the variance of the signal-to-noise ratio of the pilot subcarrier, the calibration factor and the mean value of the signal-to-noise ratio of the pilot subcarrier, and the reference signal-to-noise ratio is used to switch the adaptive modulation coding transmission mode.

[0008] Furthermore, the method for obtaining the reference signal-to-noise ratio is: using the mean of the signal-to-noise ratio of the pilot subcarrier minus the product of the variance of the signal-to-noise ratio of the pilot subcarrier and the calibration factor to obtain the reference signal-to-noise ratio.

[0009] Furthermore, the calibration factor is an average value of the weights of each pilot subcarrier.

[0010] Further, when the reference signal-to-noise ratio is used to switch the adaptive modulation and coding transmission mode, the reference signal-to-noise ratio is an equivalent signal-to-noise ratio corrected according to the receiving and decoding situation.

[0011] Furthermore, the calculation formula for correcting the reference signal-to-noise ratio according to the receiving and decoding situation is:

[0012] SNR eff =SNR ref +Δ snr ;

[0013] Among them, SNR eff is the equivalent signal-to-noise ratio, Δ snr It is the correction value of the signal-to-noise ratio. During the coding and modulation process, the equivalent signal-to-noise ratio is updated as the receiving node receives and decodes the result. When the receiving node receives and decodes successfully, the equivalent signal-to-noise ratio increases. When the receiving node fails to decode, the equivalent signal-to-noise ratio decreases.

[0014] Furthermore, the calculation formula of the signal-to-noise ratio correction value is:

[0015] Δ snr =Δ snr +Δ up ·(1-e blk )-Δ down ·e blk ;

[0016] Among them, e blk The receiving node receives the decoding result indication; when the receiving node receives the decoding successfully, e blk =0; when the receiving node fails to receive and decode, e blk =1;Δ up is the step size for increasing the signal-to-noise ratio; Δ down The step size for reducing the signal-to-noise ratio.

[0017] Furthermore, the step size of the signal-to-noise ratio reduction is Δ down The calculation formula used is:

[0018]

[0019] Among them, BLER target is the target block error rate of the system.

[0020] Furthermore, the signal-to-noise ratio threshold value of the transmission mode used when switching the adaptive modulation and coding transmission mode is the signal-to-noise ratio of the transmission mode corresponding to when the modulation and coding transmission mode reaches a target block error rate.

[0021] Furthermore, the estimation formula of the signal-to-noise ratio of the pilot subcarrier is:

[0022]

[0023] Where, Y(l,k) is the frequency domain received signal on the kth subcarrier of the lth pilot symbol, L is the total number of pilot symbols, SNR(k) is the signal-to-noise ratio on the kth pilot subcarrier, real(·) represents the real part of the complex number, and Y(l,k) * represents the conjugate of Y(l,k), E[·] represents the expected value, and |Y(l,k)| represents the modulus of Y(l,k).

[0024] A computer storage medium includes a processor and is used to store a computer program.

[0025] The beneficial effects of the present invention are as follows: as an improved invention, the present invention estimates the signal-to-noise ratio of each pilot subcarrier in the leading symbol, and obtains the reference signal-to-noise ratio by using the variance of the signal-to-noise ratio of the pilot subcarrier, the calibration factor and the mean of the signal-to-noise ratio of the pilot subcarrier, wherein the calibration factor is based on, the obtained reference signal-to-noise ratio is closer to the real signal-to-noise ratio, and the error between the reference signal-to-noise ratio and the real signal-to-noise ratio is reduced, so that when the reference signal-to-noise ratio is used to switch the adaptive modulation coding transmission mode, it can be avoided that the error of the estimated signal-to-noise ratio is large, resulting in the selected coding transmission mode being unsuitable for the current transmission situation, thereby improving the communication reliability and communication efficiency. The transmission efficiency of the communication system is improved, and it has a high application value in the power line carrier communication system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a diagram of the physical layer data unit frame structure in an embodiment of the present invention.

[0027] Figure 2 Schematic diagram of the format of the leading symbol in the embodiment of the present invention.

[0028] Figure 3 It is a simulation performance diagram of different modulation coding transmission modes of AWGN channel PB520 in an embodiment of the present invention.

[0029] Figure 4 It is a schematic diagram of the process of switching the adaptive modulation and coding transmission mode in an embodiment of the present invention.

[0030] Figure 5 It is a structural diagram of the functional unit of adaptive modulation and coding in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0032] The present invention estimates the signal-to-noise ratio of each pilot subcarrier, and uses the variance of the signal-to-noise ratio of the pilot subcarrier, the calibration factor and the mean of the signal-to-noise ratio of the pilot subcarrier to obtain a reference signal-to-noise ratio, thereby improving the accuracy of the signal-to-noise ratio calculation and avoiding a large gap between the estimated signal-to-noise ratio and the actual signal-to-noise ratio, which leads to an inability to accurately judge whether the current transmission mode is appropriate. The present invention improves the transmission efficiency of the communication system and has a high application value in the power line carrier communication system.

[0033] Method Embodiment

[0034] In the State Grid high-speed power line carrier communication technology standard, the physical layer protocol data unit (PPDU) signal frame structure sent by the physical layer is as follows: Figure 1 As shown in the figure, PPDU consists of preamble, frame control and payload data. The preamble is a periodic sequence with 512 pilot subcarriers per symbol. Figure 2 In the State Grid high-speed power line carrier communication system, the receiving node mainly estimates the channel quality based on the preamble.

[0035] The State Grid high-speed power line carrier communication technology standard provides 26 modulation coding transmission modes for ACM technology, as shown in Table 1 (diversity copy basic mode, a total of 15 modes) and Table 2 (diversity copy extended mode, a total of 11 modes).

[0036] Table 1 Basic modes of episode copying

[0037]

[0038]

[0039] Table 2 Diversity copy extension mode

[0040]

[0041] Due to the different effects of different coding rates and modulation modes in the transmission process, the present invention simulates the performance of these 26 modulation coding transmission modes under the additive white Gaussian noise (AWGN) channel. More intuitively, the simulation results of several typical modulation coding transmission modes of PB520 are selected to draw the corresponding SNR-BLER curves, as shown in FIG. Figure 3 As shown in the figure, the horizontal axis represents the signal-to-noise ratio and the vertical axis represents the bit error rate. Figure 3It can be seen that as the signal-to-noise ratio changes, the bit error rate of different transmission modes changes accordingly. When the bit error rate reaches the critical value of the target bit error rate, the bit error rate can be controlled not to exceed the target bit error rate by switching the transmission mode. In order to ensure a block error rate of 10%, the signal-to-noise ratio value when these modulation and coding transmission modes reach a block error rate of 10% is set as the threshold value. Considering the consistency of the transmission block size during compatible retransmission, the 26 modulation and coding transmission modes are re-divided according to the transmission block size and spectrum efficiency. The final modulation and coding transmission mode mapping table (modulation and coding transmission mode switching threshold value table) is shown in Table 3 below.

[0042] Table 3 Modulation coding transmission mode switching threshold table

[0043]

[0044] It can be seen that due to the threshold value T n It has been determined that the main factor affecting the performance of the AMC system is the calculation method of the equivalent signal-to-noise ratio.

[0045] However, in the prior art, the signal-to-noise ratio is the pilot subcarrier signal-to-noise ratio calculated by the receiving end through the measurement module. Under low signal-to-noise ratio, the noise power plays a dominant role. At this time, the pilot subcarrier signal-to-noise ratio calculated is larger than the pilot subcarrier signal-to-noise ratio calculated under accurate channel estimation. Under high signal-to-noise ratio, the noise power is relatively small. At this time, the pilot subcarrier signal-to-noise ratio calculated is similar to the pilot subcarrier signal-to-noise ratio calculated under accurate channel estimation. However, in actual situations, due to the "flat bottom effect" of the noise power measurement value under high signal-to-noise ratio, the noise power at the receiving end cannot tend to 0, but tends to a certain value greater than 0. Therefore, the pilot subcarrier signal-to-noise ratio under channel estimation is smaller than the pilot subcarrier signal-to-noise ratio under accurate channel estimation. Therefore, the adaptive performance of the link is closely related to the signal-to-noise ratio value, and the accuracy of the signal-to-noise ratio value will directly affect the performance of the entire system.

[0046] Considering the influence of fading channels and external environment, the present invention first obtains the signal-to-noise ratio of each pilot subcarrier on the leading symbol, then calculates different weight values ​​of each subcarrier under the influence of the channel, then takes the mean of different weights as the calibration factor, and calibrates the mean of the pilot subcarrier in combination with the variance of the pilot subcarrier to obtain a reference signal-to-noise ratio, then corrects the reference signal-to-noise ratio according to the receiving decoding result of the receiving end to obtain an equivalent signal-to-noise ratio, and finally selects the modulation coding transmission mode according to the equivalent signal-to-noise ratio.

[0047] like Figure 4 As shown, a carrier communication modulation and coding method comprises the following steps:

[0048] S1: Receive signal frame data through the receiving node and estimate the reference signal-to-noise ratio (SNR) of the received signal based on the leading symbol in the signal frame.ref .

[0049] S11: Calculate the signal-to-noise ratio SNR(k) of the pilot subcarrier based on the pilot symbol estimation. The specific formula is as follows:

[0050]

[0051] Wherein, Y(l,k) is the frequency domain received signal on the kth pilot subcarrier of the lth pilot symbol, 0<k≤511, L is the total number of pilot symbols, and L=12 in this embodiment. SNR(k) is the signal-to-noise ratio on the kth pilot subcarrier. real(·) means taking the real part of the complex number, Y(l,k) * represents the conjugate of Y(l,k). E[·] represents the expected value. |Y(l,k)| represents the modulus of Y(l,k).

[0052] S12: Calculate different weights f1(k) of the pilot subcarriers on the pilot symbol under the influence of the channel. The specific calculation method is as follows:

[0053]

[0054] Wherein, k represents the kth pilot subcarrier, K is the number of valid pilot subcarriers, and in this embodiment, K≤512. SNR(k) is the signal-to-noise ratio on the kth pilot subcarrier.

[0055] S13: Take the mean of different weights f1(k) as the calibration factor f, that is:

[0056]

[0057] As another implementation, the calibration factor here may also be obtained by using other schemes, such as taking the median.

[0058] S14: Calculate the mean value μ of the signal-to-noise ratio of the pilot subcarrier snr With variance σ snr , and using the variance σ snr The mean value μ of the signal-to-noise ratio of the pilot subcarrier and the calibration factor f snr Perform calibration to obtain the reference signal-to-noise ratio SNR ref .

[0059] Get the reference signal-to-noise ratio SNR ref The formula is as follows:

[0060] SNR ref =μ SNR -f·σ SNR ;

[0061] Among them, the mean signal-to-noise ratio of the pilot subcarrier is The variance of the pilot subcarrier signal-to-noise ratio

[0062] S2: The sending node calculates the reference signal-to-noise ratio (SNR) based on the received decoding situation. ref Correction is performed to obtain the corrected equivalent signal-to-noise ratio SNR eff .

[0063] The specific method is as follows:

[0064] SNR eff =SNR ref +Δ snr ;

[0065] Among them, Δ snr It is the correction value of the signal-to-noise ratio. During the coding and modulation process, the equivalent signal-to-noise ratio is updated as the receiving node receives and decodes the result. When the receiving node receives and decodes successfully, the equivalent signal-to-noise ratio increases. When the receiving node fails to decode, the equivalent signal-to-noise ratio decreases.

[0066] Signal-to-noise ratio correction value Δ snr The update method is as follows:

[0067] Δ snr =Δ snr +Δ up ·(1-e blk )-Δ down ·e blk ;

[0068] Among them, e blk The receiving node receives the decoding result indication: when the receiving node receives the decoding successfully, e blk =0; when the receiving node fails to receive and decode, e blk =1. Δ up The step size for increasing the signal-to-noise ratio can be flexibly configured according to the system. To avoid excessive mode switching adjustments that may cause system instability, the step size should be less than or equal to 1dB, and can generally be 0.5dB or 1dB. down is the step size for decreasing the signal-to-noise ratio, and the step size for increasing the signal-to-noise ratio can be Δ up and the target block error rate BLER of the system target The signal-to-noise ratio correction value is continuously updated and changed during the coding and modulation process to ensure the equivalent signal-to-noise ratio SNR eff Accuracy ensures system performance.

[0069] Δ down The specific configuration method is as follows:

[0070]

[0071] In this embodiment, the target block error rate BLER of the systemtarget The value is 0.1 (i.e. 10%).

[0072] S3: The sending node is based on the equivalent signal-to-noise ratio SNR eff , the fixed threshold method is used to switch the adaptive modulation and coding transmission mode.

[0073] Specifically, the sending node calculates the equivalent signal-to-noise ratio SNR. eff Query the preset modulation coding transmission mode switching threshold value table. If the equivalent signal-to-noise ratio SNR at the current moment is eff The equivalent signal-to-noise ratio SNR at the previous moment eff If the SNR is within the corresponding signal-to-noise ratio threshold, the modulation and coding transmission mode does not need to be switched at this time, and the transmission is performed according to the modulation and coding transmission mode of the previous moment; if the equivalent signal-to-noise ratio SNR at the current moment is eff Exceeds the equivalent signal-to-noise ratio SNR of the previous moment eff If the signal-to-noise ratio threshold value is within the range, the equivalent signal-to-noise ratio SNR at the current moment is obtained. eff The corresponding modulation and coding transmission mode parameters are sent to the receiving node according to the modulation and coding transmission mode parameters, the modulation and coding transmission mode is switched, and steps S1-S3 are repeated.

[0074] According to the equivalent signal-to-noise ratio SNR eff Select the modulation and coding transmission mode according to the following formula:

[0075]

[0076] Among them, TMI p (p = 0, 1, 2, ..., P-1) represents a modulation coding transmission mode indication under a physical block length, corresponding to different modulation modes or coding rates. p Represents the signal-to-noise ratio threshold, T p <T p+1 (p=0,1,2,...,P-1), the signal-to-noise ratio value when the modulation coding transmission mode reaches the target block error rate is the signal-to-noise ratio threshold value. refWhen switching the adaptive modulation and coding transmission mode, the signal-to-noise ratio threshold value is the reference signal-to-noise ratio value of the signal-to-noise ratio value when the transmission mode reaches the target block error rate; when using the equivalent signal-to-noise ratio to switch the adaptive modulation and coding transmission mode, the signal-to-noise ratio threshold value is the equivalent signal-to-noise ratio value of the signal-to-noise ratio value when the transmission mode reaches the target block error rate. The threshold value is formulated by the signal-to-noise ratio value corresponding to the target block error rate, which effectively links the block error rate with the signal-to-noise ratio. During the modulation and coding process, when the actual block error rate is higher than the target block error rate, the equivalent signal-to-noise ratio value also exceeds the threshold value range corresponding to the transmission mode. At this time, the system will automatically change the transmission mode to realize the adaptive coding modulation of the system, so that the actual block error rate of the system during operation is always lower than the automatic block error rate, ensuring the normal and efficient operation of the system. P is the number of modulation and coding transmission modes contained in a physical block length, as shown in Table 3. In this embodiment, PB520 contains a total of P=12 modulation and coding transmission modes. n is the modulation coding transmission mode index start offset value included in the physical block length. In this embodiment, the modulation coding transmission mode index start offset value n included in PB520 is 14. For example, for PB520, when -7.87dB≤SNR eff When <-6.84dB, the modulation coding transmission mode TMI15 is adopted.

[0077] In the present invention, the switching of modulation coding transmission mode adopts a fixed threshold method, dual binary Turbo code is used as the coding and decoding strategy, BPSK / QPSK / 16QAM is used as the modulation and demodulation scheme, and the switching of system modulation coding transmission mode is based on the equivalent signal-to-noise ratio of the transmitting end.

[0078] As another implementation, the signal-to-noise ratio used when switching the adaptive modulation and coding transmission mode using the fixed threshold method may also be a reference signal-to-noise ratio.

[0079] Computer Storage Medium Embodiments

[0080] A computer storage medium includes a processor, and the computer storage medium is used to store a computer program. Figure 5 As shown, the computer program can be divided into a pilot subcarrier signal-to-noise ratio calculation unit, a reference signal-to-noise ratio calibration factor calculation unit, a reference signal-to-noise ratio calculation unit, an equivalent signal-to-noise ratio calculation unit and a transmission mode parameter selection unit.

[0081] The pilot subcarrier signal-to-noise ratio calculation unit is mainly used to estimate the signal-to-noise ratio SNR(k) of the pilot subcarrier according to the pilot symbol in step S11. The reference signal-to-noise ratio calibration factor calculation unit is mainly used to calculate the different weights f1(k) of the pilot subcarrier on the pilot symbol under the influence of the channel in steps S12-S13, and take the average of the different weights f1(k) as the calibration factor f. The reference signal-to-noise ratio calculation unit is mainly used in step S14 to calculate the variance σsnr The mean value μ of the signal-to-noise ratio of the pilot subcarrier and the calibration factor f snr Perform calibration to obtain the reference signal-to-noise ratio SNR ref The equivalent signal-to-noise ratio calculation unit is mainly used in step S3 to calculate the reference signal-to-noise ratio SNR according to the receiving and decoding conditions. ref Correction is performed to obtain the corrected equivalent signal-to-noise ratio SNR eff The transmission mode parameter selection unit is mainly used in step S4 to select the transmission mode parameter based on the equivalent signal-to-noise ratio SNR. eff , obtain the corresponding modulation coding transmission mode parameters. In step S14, the mean value μ of the signal-to-noise ratio of the pilot subcarrier is calculated. snr With variance σ snr In step S2, the receiving node refers to the signal-to-noise ratio SNR ref The receiving and decoding conditions are fed back to the sending node through the existing program in the processor. The specific implementation process has been described in detail in the method embodiment, and will not be repeated here.

Claims

1. A method for adaptive modulation and coding of carrier communication, characterized in that the steps include: The signal-to-noise ratio of each pilot subcarrier in the pilot symbol is estimated according to the frequency domain received signal of each subcarrier in the pilot symbol, and the proportion of the signal-to-noise ratio of each pilot subcarrier in the total pilot subcarriers is used as the weight of the corresponding pilot subcarrier under the influence of the channel; the calibration factor is obtained according to the weight of each pilot subcarrier; the reference signal-to-noise ratio is obtained by using the variance of the signal-to-noise ratio of the pilot subcarrier, the calibration factor and the mean value of the signal-to-noise ratio of the pilot subcarrier, and the reference signal-to-noise ratio is used to switch the adaptive modulation coding transmission mode.

2. The method for carrier communication adaptive modulation and coding according to claim 1, characterized in that: The method for obtaining the reference signal-to-noise ratio is: using the mean value of the signal-to-noise ratio of the pilot subcarrier minus the product of the variance of the signal-to-noise ratio of the pilot subcarrier and the calibration factor to obtain the reference signal-to-noise ratio.

3. The method for carrier communication adaptive modulation and coding according to claim 2, characterized in that: The calibration factor is the average value of the weights of each pilot subcarrier.

4. The method for carrier communication adaptive modulation and coding according to any one of claims 1 to 3, characterized in that: The reference signal-to-noise ratio when switching the adaptive modulation and coding transmission mode using the reference signal-to-noise ratio is an equivalent signal-to-noise ratio corrected according to the receiving and decoding situation.

5. The method for carrier communication adaptive modulation and coding according to claim 4, characterized in that: The calculation formula for correcting the reference signal-to-noise ratio according to the receiving and decoding situation is: SNR eff =SNR ref +Δ snr ; Among them, SNR eff is the equivalent signal-to-noise ratio, Δ snr It is the correction value of the signal-to-noise ratio. During the coding and modulation process, the equivalent signal-to-noise ratio is updated as the receiving node receives and decodes the result. When the receiving node receives and decodes successfully, the equivalent signal-to-noise ratio increases. When the receiving node fails to decode, the equivalent signal-to-noise ratio decreases.

6. The method for carrier communication adaptive modulation and coding according to claim 5, characterized in that: The calculation formula of the signal-to-noise ratio correction value is: D snr =D snr +D up ·(1-e blk )-D down ·e blk ; Among them, e blk The receiving node receives the decoding result indication; when the receiving node receives the decoding successfully, e blk =0; when the receiving node fails to receive and decode, e blk =1;Δ up is the step size for increasing the signal-to-noise ratio; Δ down The step size for reducing the signal-to-noise ratio.

7. The method for carrier communication adaptive modulation and coding according to claim 6, characterized in that: The step value of signal-to-noise ratio reduction Δ down The calculation formula used is: Among them, BLER target is the target block error rate of the system.

8. The method for carrier communication adaptive modulation and coding according to claim 1, characterized in that: The signal-to-noise ratio threshold value of the transmission mode used when switching the adaptive modulation and coding transmission mode is the signal-to-noise ratio of the transmission mode corresponding to the modulation and coding transmission mode when the target block error rate is reached.

9. The method for carrier communication adaptive modulation and coding according to claim 1, characterized in that: The estimation formula of the signal-to-noise ratio of the pilot subcarrier is: Where, Y(l,k) is the frequency domain received signal on the kth subcarrier of the lth pilot symbol, L is the total number of pilot symbols, SNR(k) is the signal-to-noise ratio on the kth pilot subcarrier, real(·) represents the real part of the complex number, and Y(l,k) * represents the conjugate of Y(l,k), E[·] represents the expected value, and |Y(l,k)| represents the modulus of Y(l,k).

10. A computer storage medium, characterized in that: The computer storage medium comprises a processor, and the computer storage medium is used to store a computer program to implement the method for adaptive modulation and coding of carrier communication as described in any one of claims 1 to 9.

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