Frame control adaptive coding method based on preamble sequence implicit channel quality indication

Abstract

The application discloses a frame control adaptive coding method based on a preamble sequence implicit channel quality indication, and comprises the following steps: constructing a first mapping relationship between a generation parameter of a preamble sequence and a frame control modulation coding strategy; a sending end traverses the first mapping relationship according to channel quality estimation, determines an MCS level and the generation parameter, generates a preamble sequence and FC coding data according to the generation parameter; and a receiving end executes a parallel multi-root detection mechanism in a preamble sequence synchronization stage, decodes the FC coding data to obtain a modulation coding strategy. The application takes the generation parameter selection of the preamble sequence as an implicit indication means of the frame control information modulation coding scheme, so that the receiving end can obtain the modulation coding scheme of the frame control information at the same time of completing preamble synchronization, solves the problem that FC loses demodulation parameters due to demodulation failure caused by channel fluctuation, and improves the stability of the frame control information modulation coding scheme transmission.

Description

Technical Field

[0001] The invention relates to the field of communication control technology, and in particular to a frame control adaptive coding method based on a preamble sequence implicit channel quality indication. Background Technology

[0002] In the PLC (Power Line Communication) physical layer protocol defined in the State Grid's "Dual-Mode Communication Interconnection Technical Specification," the frame control symbol carries key demodulation parameters for data frames (such as modulation and coding scheme MCS, data length, pilot pattern, etc.), which is a prerequisite for the receiver to correctly parse subsequent data payloads. This protocol stipulates that the frame control symbol adopts a fixed robust coding scheme (such as repetitive coding combined with BPSK modulation) to ensure reliable reception even under the worst channel conditions.

[0003] In existing power line communication standards and protocols, the transmission of frame control information generally employs a fixed modulation and coding scheme that does not change with channel conditions. Representative existing schemes include the following three categories: (a) Fixed Robust Coding Scheme: Represented by ITU-T G.9903 (G3-PLC) and G.9904 (PRIME) standards, the frame control symbols are fixedly encoded using BPSK (Binary Phase Shift Keying) modulation combined with highly redundant forward error correction coding (such as 1 / 2 rate convolutional code plus repetition coding), and are transmitted with the same set of parameters under any channel conditions. The FC symbols in the current dual-mode communication protocol of the State Grid also follow this paradigm, that is, the frame control information is transmitted with a fixed coding rate and modulation order, and the receiving end processes it with a fixed demodulation method.

[0004] While fixed robust coding schemes guarantee reception reliability under worst-case channel conditions, they result in significant spectral efficiency waste in medium-to-high signal-to-noise ratio channels (such as short-range communication and periods with favorable channel conditions). For example, comparing BPSK to QPSK (Quadrature Phase Shift Keying), QPSK can transmit twice the amount of information within the same bandwidth, while a fixed BPSK scheme cannot utilize this channel capacity. In PLC channels, channel conditions fluctuate significantly with factors such as grid load, the number of connected devices, and time periods. A fixed scheme means the system always operates with the "lowest common denominator," limiting overall throughput.

[0005] (b) Explicit Signaling Indication Scheme: Represented by the SIGNAL field in the IEEE 802.11 (Wi-Fi) series: The physical layer frame header contains an independent signaling field, which is transmitted in the most robust mode (such as BPSK + 1 / 2 bit rate). The content of this field explicitly indicates the modulation and coding scheme of the subsequent data portion. In the HomePlug AV standard in the PLC field, the frame control field also adopts a similar approach: several bits inside the FC (Frame Control) are used to identify the modulation method and bit rate of the subsequent payload.

[0006] However, the transmission of the frame control signaling field itself still relies on fixed robust coding, and the bits occupied by this field are themselves valuable physical layer overhead. When the signaling field fails to demodulate due to channel degradation, not only is the MCS (Modulation and Coding Scheme) information lost, but the entire data frame cannot be parsed. More importantly, in a high-impulse-noise channel like PLC, the reception reliability of FC symbols cannot always be guaranteed; once FC demodulation fails, even if subsequent data symbols are transmitted with a high MCS (indicating that the channel conditions are actually good), the receiver has no way of knowing its demodulation parameters, resulting in the loss of the entire frame. In other words, the FC symbol itself becomes a single point of failure in terms of reliability.

[0007] (c) Independent Channel Quality Feedback Scheme: The receiver measures channel quality parameters (such as the estimated signal-to-noise ratio SNR) and sends the recommended MCS to the peer via the uplink feedback channel. The transmitter adjusts the coding scheme of subsequent frames based on the feedback. A typical protocol is the CQI (Channel Quality Indicator) reporting mechanism in 3GPP LTE / NR.

[0008] However, this approach requires establishing and maintaining a two-way feedback link, introducing additional interaction latency. In PLC point-to-multipoint communication scenarios (such as communication between a concentrator and multiple meters), the central node needs to maintain independent channel quality status for each terminal, significantly increasing protocol complexity. Furthermore, the feedback information itself requires physical layer resources, also presenting transmission reliability issues.

[0009] In summary, the common drawback of existing technologies is that there is a lack of efficient coupling mechanism between the modulation and coding scheme of frame control information and the channel conditions in which it is located—either there is no coupling at all (fixed scheme), or coupling can only be achieved by consuming the frame control bits themselves (explicit signaling), or it relies on an additional feedback loop (independent feedback). Summary of the Invention

[0010] To address the technical problem of low transmission stability of modulation and coding schemes for frame control information due to changes in channel conditions in existing technologies, this invention proposes a frame control adaptive coding method based on implicit channel quality indication of the preamble sequence. This method utilizes the parameter selection of the preamble sequence itself to implicitly carry the modulation and coding scheme indication of the frame control information, enabling the receiver to obtain the modulation and coding scheme of the frame control information while completing preamble synchronization, thereby improving stability.

[0011] To achieve the above objectives, the present invention provides the following technical solution: The frame control adaptive coding method based on preamble sequence implicit channel quality indication specifically includes the following steps: S1: Construct the first mapping relationship between the generation parameters of the preamble sequence and the frame control modulation and coding strategy; S2: The transmitter traverses the first mapping relationship based on the channel quality estimate to determine the MCS level and generation parameters, and generates the preamble sequence and FC encoded data based on the generation parameters; S3: The receiver executes a parallel multi-root detection mechanism during the preamble sequence synchronization phase to complete the decoding of FC encoded data and obtain the modulation and coding strategy.

[0012] Preferably, in S1, the generation parameters of the leader sequence include the root number of the ZC sequence, the cyclic shift amount, and / or the initial phase rotation angle.

[0013] Preferably, in step S2, the method for determining the MCS level is as follows: In a two-way communication scenario, after demodulating the previous frame, the receiver feeds back the channel quality indicator to the transmitter through the upper-layer protocol, and the transmitter selects the MCS level based on the feedback value.

[0014] Preferably, in step S2, the method for determining the MCS level is as follows: In time-division duplex mode, the transmitter infers the forward channel quality indication and determines the MCS level by measuring the SNR of the reverse received signal.

[0015] Preferably, in step S2, the method for determining the MCS level is as follows: The sending end maintains a sliding window of ACK / NACK history. If the NACK ratio in the most recent M frames is lower than the threshold T1, the MCS level is increased by one level; if it is higher than the threshold T2, the MCS level is decreased by one level.

[0016] Preferably, in step S2, the data is encoded and symbol mapped according to the modulation and coding strategy corresponding to the MCS level to obtain FC encoded data.

[0017] Preferably, S3 includes: S3-1: During the preamble sequence synchronization phase, K replicas are used to simultaneously perform K frequency domain cross-correlation calculations to obtain K calculation results; S3-2: Take the preamble sequence with the largest amplitude among the K calculation results as the decision result to determine the corresponding MCS level and frame control modulation and coding strategy; S3-3: Simultaneously, a frequency domain synchronization algorithm is used to extract FC encoded data; S3-4: Demodulate and decode the FC encoded data according to the frame control modulation and coding strategy corresponding to the decision result to obtain the modulation and coding strategy.

[0018] Preferably, in step S3-1, the receiving end maintains copies of K candidate preamble sequences locally, corresponding to K possible root numbers.

[0019] Preferably, in S3-3, the FC encoded data includes an adjusted encoding strategy.

[0020] Preferably, it also includes a correction mechanism: The decision result is verified and confirmed using the check bit of the FC demodulation result: if the FC CRC check fails, the MCS corresponding to the second-ranked preamble sequence among the K calculation results is used to re-demodulate the FC encoded data.

[0021] In summary, by adopting the above technical solution, the present invention has at least the following beneficial effects compared with the prior art: 1. This invention uses the selection of preamble generation parameters as an implicit indication of the modulation and coding scheme of frame control information. The receiving end can know the modulation and coding scheme of frame control information at the same time as completing preamble synchronization, which solves the problem of FC losing demodulation parameters due to channel fluctuation demodulation failure and improves the transmission stability of the modulation and coding scheme of frame control information.

[0022] 2. The generation parameters of the preamble sequence do not incur additional signaling overhead, thus saving this part of the physical layer overhead.

[0023] 3. The receiver employs parallel detection, simultaneously performing frequency domain cross-correlation on K possible candidate preamble sequence parameters, and using the candidate parameter corresponding to the maximum correlation value as the decision result, thereby completing the extraction of synchronization parameters and recovery of MCS information in one go, which improves processing efficiency. Attached image description: Figure 1 This is a schematic diagram of a frame control adaptive coding method based on a preamble sequence implicit channel quality indication according to an exemplary embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the FC encoded data decoding process according to an exemplary embodiment of the present invention. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to embodiments and specific implementation methods. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0026] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0027] like Figure 1 As shown, this invention provides a frame control adaptive coding method based on a preamble sequence implicit channel quality indication, specifically including the following steps: S1: Construct the first mapping relationship between the generation parameters of the preamble sequence and the frame control modulation and coding strategy.

[0028] In this embodiment, the OFDM (Orthogonal Frequency Division Multiplexing) symbol parameters follow the PLC physical layer settings of the State Grid dual-mode communication protocol. The core parameters are as follows: the total number of OFDM symbol subcarriers N=1024 (including DC and guard band), of which there are 512 effective data subcarriers and 512 odd subcarriers.

[0029] In this embodiment, the generation parameters of the preamble sequence include the root index of the ZC sequence, the cyclic shift amount, the initial phase rotation angle, or any combination of the above parameters. The core of mapping the generation parameters of the preamble sequence to the frame control modulation and coding strategy is to extend the "identification" function of the physical layer synchronization sequence to a joint "synchronization + signaling" bearer function, so that the receiving end can obtain the frame control modulation and coding strategy without additional signaling overhead while completing the preamble sequence synchronization.

[0030] The selection of parameters for generating the preamble sequence does not occupy any additional subcarriers, OFDM symbols, or bits; the MCS information is implicitly carried entirely by the parameters of the preamble sequence. Compared to explicit signaling schemes (Wi-Fi SIGNAL field, MCS bits within the FC of HomePlug AV), this invention saves this portion of physical layer overhead. Taking K=4 (2 bits of information) as an example, if an explicit signaling scheme is used, these 2 bits need to be carried by BPSK + repetitive coding, which may use 1 / 4 code rate in extremely robust mode, i.e., equivalent to occupying 8 coding bits; this invention does not require additional bits, reducing this portion of physical layer overhead to zero.

[0031] Furthermore, the ZC (Zadoff-Chu) sequence, due to its constant envelope, zero autocorrelation (CAZAC), and excellent cross-correlation characteristics, is widely used for preamble sequence synchronization in OFDM systems. Meanwhile, the ZC sequence is already a preamble sequence type defined in the State Grid dual-mode communication protocol. This invention only expands the root number selection range at the transmitting end and the number of parallel correlation paths at the receiving end, without modifying fundamental parameters such as frame structure, subcarrier mapping, guard interval, and pilot pattern, making it fully compatible with existing protocol systems. Receivers supporting this scheme can seamlessly receive signals from transmitters that do not support it (simply by degrading the candidate root set at the receiver to a single root containing only u=1). Similarly, legacy receivers that do not support this scheme can still normally receive signals transmitted with u=1 and fall back to the fixed MCS mode. This progressive deployment capability is crucial for practical engineering implementation.

[0032] For example, this invention utilizes the parameter selection of the preamble sequence itself to implicitly carry modulation and coding scheme indications for frame control information. Specifically, taking advantage of the low cross-correlation between different ZC root sequences, at the transmitting end, based on the channel quality estimate, a candidate root number is selected from a predefined set of K candidate root numbers to generate the preamble sequence, which is then directly mapped to the modulation and coding strategy of subsequent FC symbols, as shown in Table 1.

[0033] Table 1. Mapping Table between Preamble Sequence and Frame Control Modulation and Coding Strategy In this embodiment, the root numbers (1, 5, 13, 25) given in Table 1 are only examples. The actual selection should ensure that the cross-correlation of the ZC sequences between different root numbers is low enough (the larger the difference between the root numbers, the lower the cross-correlation) to guarantee the reliability of parallel detection.

[0034] S2: The transmitter traverses the first mapping relationship based on the channel quality estimate to determine the MCS level and root number, and generates a preamble sequence and FC encoded data based on the root number.

[0035] In this embodiment, before generating each transmission frame, the transmitting end needs to obtain the quality estimate of the current channel to determine the MCS level to be selected (as is the prior art), and then determine the corresponding ZC root number from the first mapping relationship according to the MCS level.

[0036] Depending on the specific scenario of the system implementation, the transmitting end can use any one or more of the following methods to obtain channel quality estimates: (a) Based on reverse channel feedback: In a two-way communication scenario, after demodulating the previous frame, the receiver feeds back the channel quality indication (such as signal-to-noise ratio estimate, bit error rate statistics, etc.) to the transmitter through the upper layer protocol. The transmitter selects the MCS level by looking up the table (preset channel quality and MSC level correspondence table) based on the feedback value.

[0037] (b) Channel reciprocity-based prediction: In time division duplex (TDD) mode, the short-time reciprocity of the PLC channel is utilized. The transmitting end infers the forward channel quality estimate by measuring the SNR of the reverse received signal, and then determines the MCS level according to the preset channel quality and MSC level correspondence table. This method does not require explicit feedback and has the lowest latency.

[0038] (c) Adaptive based on historical statistics: The sender maintains the ACK / NACK history within a sliding window; if the NACK ratio in the most recent M frames is lower than the threshold T1, the MCS is increased by one level; if it is higher than the threshold T2, the MCS is decreased by one level; this method is the simplest to implement, but the convergence speed is slightly slower.

[0039] In this embodiment, after the transmitting end determines the MCS level, it retrieves the corresponding ZC root number u from the first mapping relationship, generates the preamble sequence under the root number according to the standard ZC sequence formula, and maps it to the transmitting subcarrier through IFFT (inverse Fourier transform).

[0040] In this embodiment, the FC data portion is encoded and symbol mapped according to the modulation and coding strategy corresponding to the root number to obtain FC encoded data.

[0041] Furthermore, it should be noted that the selection of the ZC root sequence number only affects the content of the transmitted preamble sequence, and does not change the subcarrier position, symbol duration, guard interval or other physical layer parameters occupied by the preamble. Therefore, it is fully compatible with the frame structure of existing protocols.

[0042] S3: During the preamble sequence synchronization phase, the receiver executes a parallel multi-root detection mechanism to decode the FC-coded data and obtain the modulation and coding strategy (i.e., the final result required by this invention). Figure 2 As shown.

[0043] The core processing flow of the receiver is divided into a synchronization stage and a demodulation stage. In the traditional synchronization stage, the receiver uses a single preset ZC sequence (with a known and fixed root sequence number) to correlate with the received signal to obtain frame timing and frequency offset estimation. That is, the timing is obtained by synchronization first, and then the FC is demodulated to obtain the MCS.

[0044] This invention introduces a parallel multi-root detection mechanism during the synchronization phase, simultaneously performing frequency domain cross-correlation on K possible candidate preamble sequence parameters. The candidate parameter corresponding to the maximum correlation value is used as the decision result, completing the extraction of synchronization parameters and recovery of MCS information in one go. The additional computation at the receiving end is only K-way parallel correlation, and the computational increment is within the processing capability of existing baseband chips.

[0045] S3-1: During the preamble sequence synchronization phase, K copies are used to simultaneously perform K frequency domain cross-correlation calculations to obtain K calculation results.

[0046] In this embodiment, the receiver maintains K copies of candidate preamble sequences (ZC sequences) locally, corresponding to K possible root indices {u_1, u_2, ..., u_K}. During frequency domain synchronization (e.g., after performing an FFT on the received OFDM symbols and extracting frequency domain data from even-numbered subcarriers), the K copies simultaneously perform K-way frequency domain cross-correlation operations. Frequency domain cross-correlation operations are existing technology and will not be described again here.

[0047] S3-2: Take the preamble sequence with the largest amplitude (or power) among the K calculation results as the decision result and determine the corresponding frame control modulation and coding strategy.

[0048] S3-3: While calculating the decision result, the conventional frequency domain synchronization algorithm is used to extract the FC coded data (including the coded modulation and coding strategy, but which needs to be decoded to be recognized).

[0049] In this embodiment, the extraction of FC encoded data and the extraction of decision results are processed in parallel, which improves processing efficiency.

[0050] S3-4: Demodulate and decode the FC encoded data according to the frame control modulation and coding strategy corresponding to the decision result to obtain the modulation and coding strategy.

[0051] In this embodiment, the corresponding frame control modulation and coding strategy can be determined by querying the MCS level from the first mapping relationship based on the decision result.

[0052] For example, if the ZC root number of the preamble sequence (ZC sequence) corresponding to the largest amplitude (or power) among the K calculation results is 5, then the corresponding frame control modulation and coding strategy is: QPSK+1 / 2 turbo code.

[0053] In this embodiment, to further improve the reliability of the decision result, the check bit (such as CRC) of the FC demodulation result can be used for verification after the decision result is obtained. If the FC CRC check fails and the receiver suspects that the root sequence number decision is incorrect, it can try to re-demodulate the FC using the MCS corresponding to the second-best matched root sequence number (i.e., the preamble sequence with the second-highest amplitude among the K calculation results), thereby realizing a low-cost anti-false judgment mechanism.

[0054] In this invention, the frame control modulation and coding strategy is not appended to the FC data, but is implicitly carried by the root sequence number of the preamble. When the preamble is used for synchronization detection, it is usually accumulated over multiple symbols (e.g., the average of 12 mixed OFDM symbols), and its detection signal-to-noise ratio is much higher than the demodulation signal-to-noise ratio of a single FC symbol. Therefore, the effective signal-to-noise ratio of the frame control modulation and coding strategy is much higher than when it is encoded inside the FC. In extreme cases, even if the FC symbol itself fails to demodulate due to sudden interference such as impulse noise, the frame control modulation and coding strategy is still usable as long as the preamble synchronization is successful—the receiver knows which demodulation parameters should be used for the FC and can apply them directly during retransmission or combined reception. This solves the problem of the FC itself being a single point of failure in explicit signaling schemes.

[0055] In another embodiment, a fixed single root number is used, but the MCS information is encoded using the cyclic shift value of the ZC sequence. That is, the transmitter uses a fixed root of u=1, but applies different cyclic shifts to the generated ZC sequence: x_{cs}[n] = x_1[(n + cs) mod N_ZC], where cs takes the values ​​of K predefined candidate shifts {cs_0, cs_1, ..., cs_{K-1}}, each shift corresponding to a different MCS. The receiver determines the cs value by detecting the position offset of the cross-correlation peak between the received signal and the local ZC sequence, thereby recovering the MCS. The advantage of this scheme is that only one root sequence needs to be generated and one correlation path needs to be performed; information can be obtained through the peak position offset.

[0056] In another embodiment, combining root number selection and cyclic shift can further expand the number of MCS levels or improve reliability. For example, using U candidate root numbers and S candidate cyclic shifts, a total of U×S MCS levels can be encoded, with an information content of log2(U×S) bits. At the receiver, the root number is first determined through multi-root correlation, and then the cyclic shift is detected near the optimal correlation peak of each root. This scheme is suitable for systems with high requirements for MCS granularity.

[0057] In another embodiment, after generating the ZC sequence, the transmitter applies an additional symbol-level complex phase rotation: x'_u[n] = exp(jφ) · x_u[n], where the phase rotation angle φ takes K predefined discrete values ​​{φ_0, φ_1, ..., φ_{K-1}}, each corresponding to a different MCS. The receiver determines the value of φ by detecting the complex phase of the correlation result after frequency domain correlation. This scheme has the lowest computational complexity (only one correlation, with an additional phase extraction step added to the correlation result), but it is significantly affected by channel phase rotation and residual frequency offset, resulting in lower reliability than the root-index scheme. It is suitable for scenarios with low MCS levels (e.g., K=2, distinguishing only between BPSK and QPSK) and predictable channel phase characteristics.

[0058] In another embodiment, a small number of subcarriers (e.g., 8) are selected from the even-numbered subcarriers occupied by the preamble sequence as MCS indicator subcarriers. These selected subcarriers do not transmit the standard ZC sequence; instead, they transmit known BPSK / QPSK symbols whose values ​​directly encode the MCS information. During the synchronization phase, the receiver first performs correlation on the non-indicator subcarriers to obtain synchronization parameters, and then extracts the MCS from the known symbols of the indicator subcarriers. The advantage of this scheme is that the MCS information and synchronization parameters are completely decoupled. The disadvantage is that modifying the ZC sequence values ​​on some subcarriers will cause a certain degree of attenuation to the synchronization cross-correlation peak. When K is small (e.g., K≤4), the number of indicator subcarriers required is small, and the peak attenuation is within an acceptable range.

[0059] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention. In practical applications of persistent media (such as server disks, NAS, and object storage), various changes in form and detail can be made without departing from the spirit and scope of the present invention.

Claims

1. A frame control adaptive coding method based on preamble sequence implicit channel quality indication, characterized in that, Specifically, the following steps are included: S1: Construct the first mapping relationship between the generation parameters of the preamble sequence and the frame control modulation and coding strategy; S2: The transmitter traverses the first mapping relationship based on the channel quality estimate to determine the MCS level and generation parameters, and generates the preamble sequence and FC encoded data based on the generation parameters; S3: The receiver executes a parallel multi-root detection mechanism during the preamble sequence synchronization phase to complete the decoding of FC encoded data and obtain the modulation and coding strategy.

2. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 1, characterized in that, In S1, the generation parameters of the leader sequence include the root number of the ZC sequence, the cyclic shift amount, and / or the initial phase rotation angle.

3. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 2, characterized in that, In S2, the method for determining the MCS level is as follows: In a two-way communication scenario, after demodulating the previous frame, the receiver feeds back the channel quality indicator to the transmitter through the upper-layer protocol, and the transmitter selects the MCS level based on the feedback value.

4. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 2, characterized in that, In S2, the method for determining the MCS level is as follows: In time-division duplex mode, the transmitter infers the forward channel quality indication and determines the MCS level by measuring the SNR of the reverse received signal.

5. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 2, characterized in that, In S2, the method for determining the MCS level is as follows: The sending end maintains a sliding window of ACK / NACK history. If the NACK ratio in the most recent M frames is lower than the threshold T1, the MCS level is increased by one level; if it is higher than the threshold T2, the MCS level is decreased by one level.

6. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 2, characterized in that, In step S2, the data is encoded and symbol mapped according to the modulation and coding strategy corresponding to the MCS level to obtain FC encoded data.

7. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 1, characterized in that, S3 includes: S3-1: During the preamble sequence synchronization phase, K replicas are used to simultaneously perform K frequency domain cross-correlation calculations to obtain K calculation results; S3-2: Take the preamble sequence with the largest amplitude among the K calculation results as the decision result to determine the corresponding MCS level and frame control modulation and coding strategy; S3-3: Simultaneously, a frequency domain synchronization algorithm is used to extract FC encoded data; S3-4: Demodulate and decode the FC encoded data according to the frame control modulation and coding strategy corresponding to the decision result to obtain the modulation and coding strategy.

8. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 7, characterized in that, In S3-1, the receiving end maintains copies of K candidate preamble sequences locally, corresponding to K possible root numbers.

9. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 7, characterized in that, In S3-3, the FC encoded data includes an adjusted encoding strategy.

10. The frame control adaptive coding method based on preamble sequence implicit channel quality indication as described in claim 7, characterized in that, It also includes a correction mechanism: The decision result is verified and confirmed using the check bit of the FC demodulation result: if the FC CRC check fails, the MCS corresponding to the second-ranked preamble sequence among the K calculation results is used to re-demodulate the FC encoded data.

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